Carnedd Dafydd Weather Forecast – 1,044m, Eryri (Snowdonia)

Monday 19 October 2026Confidence: Medium

Overall hill weather38Poor

Summit wind · 08:00-17:0020-35 mph southeasterly Summit gusts · 08:00-17:0040-50 mph Feels like-6 to -2°C PrecipitationLittle or none Cloud-free summit estimate50% Cloud base through day600-1,600 m Freezing levelAbove summit DaylightSunrise 07:49 · Sunset 18:12 · 10.4 hours daylight

The day on the hill

A poor day on the tops of Carnedd Dafydd, with strong, gusty winds.

Wind

On the summit expect a south-easterly wind of around 25–35 mph first thing, easing to 20–30 mph by mid-afternoon, with gusts of 40–50 mph at the windiest. Lower down on the open hillside it will be more like 5–15 mph. Gusts like that are strong enough to knock you off balance, so take care near edges and on narrow ridges.

Cloud and visibility

Cloud on the tops early should lift off them by early afternoon. The cloud base could be as low as 600–900 m around midday. The air should be clear, so expect far-reaching views whenever the tops come out of the cloud.

Rain and ground

It should stay dry.

Warmth and kit

On the tops it will be around 0 to 4°C, feeling like -6 to -2°C in the wind. The freezing level is above the summits. Take a hat, gloves, a windproof and a spare warm layer.

Daylight

Sunset is around 6:10pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

There is some disagreement between forecast models on wind strength. Things could still change through the day, so keep an eye on the sky.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 5.3 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 0 h
Midday: 4 h
Later: Less than 1 hour

Overnight forecast: 17:00–08:00 (UK local time), in Wild camping below.

Morning · 08:00–12:00 Poor Summit winds around 25-35 mph. Gusts around 40-50 mph are possible on exposed ground. Gusts this strong can knock you off balance, so take care near edges and on narrow ridges.

20

Afternoon · 12:00–17:00 Mixed Summit winds around 25-35 mph in the early afternoon, easing to 20-30 mph later. Gusts around 35-45 mph are possible on exposed ground. Gusts this strong can make walking into it hard work, with buffeting on ridges and edges. Summit cloud is more persistent early in this period, with better prospects later.

57

Compare an early start with later conditions. The main forecast above covers the day in more detail.

Overnight · 17:00–08:00Wild campingBetaA mixed night to camp, mainly because of the wind: gusts of about 30 mph. 59Mixed · 600 m View detailsHide details

Night beginning Monday 19 October 2026

Full overnight outlook

A mixed night to camp, mainly because of the wind. Gusts reach about 30 mph on open ground, so peg out well and use the guylines. Look for shelter from the southeast. It should stay dry. Overnight lows of about 4°C at 900 m. A 3-season bag rated to about 4°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain0.0 mm Open ground · 600 m14 mph · gusts 27 mph Morning pack-upNo wet signal Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 63%
Moonrise: Outside this window
Moonset: 00:27 next morning BST

Clear spells may allow a view of the Moon. Illumination describes the sunlit part of the Moon, not brightness at your pitch.

Overnight window: 19 Oct, 17:00 BST to 20 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m85 · promising

Wind / gust: 12 mph / 23 mph
Typical / low: 6.6°C / 6.2°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m59 · mixed

Wind / gust: 14 mph / 27 mph
Typical / low: 6.6°C / 6.2°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

900 m59 · mixed

Wind / gust: 17 mph / 32 mph
Typical / low: 4.5°C / 4.1°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 4°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

Open-hillside reference. A sheltered pitch may be calmer; cols and ridges may be much windier. Tent design and the exact pitch still matter. Read about sleeping-bag comfort ratings, pitching in strong winds or using the wild-camping forecast.

Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback

Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 40–50 mph. Poor0 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Very poor conditions for exposed scrambling. The rock should be drying, but damp patches, shaded holds and drainage lines may still be wet. Gusts of 40–50 mph could throw you off balance on exposed moves and ridges. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceDamp or dryingPeak gust40-50 mphRainPossible · 72%

Main factorsgusts of 40–50 mphdamp or incompletely dried rock possiblemuch of the route may be in cloud

Most common mapped rock around the summit Felsic tuff Capel Curig Volcanic Formation

Origin: Igneous
Broad rock-response group: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Summit area: Volcanic rock in 65% of 17 BGS samples within 350 m
Rock-response profile: Low confidence

View the summit BGS record

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Carneddau Ogwen

volcanic rock, slate or mudstone, sandstone or gritstone

Geological detail and BGS records

Mapped variation

8 rock types appear in the mapped samples

Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.

Summit-area sample Felsic tuff Capel Curig Volcanic Formation 306–680 m samples Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Route sample Mudstone and siltstone Cwm Eigiau Formation 767–860 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Siltstone Capel Curig Volcanic Formation 392–580 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Rhyolite Unnamed Igneous Intrusion, Ordovician Around 488 m Seen on Peak Carneddau Ogwen

Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.

BGS record

Route sample Sandstone Llewelyn Volcanic Group Around 955 m Seen on Peak Carneddau Ogwen

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.

BGS record

Route sample Volcaniclastic rock Foel Fras Volcanic Complex Around 1,048 m Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Summit-area sample Siltstone Llewelyn Volcanic Group

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Summit-area sample Microgabbro Unnamed Igneous Intrusion, Ordovician

Dolerite is a hard, dark, fine-grained rock. It grips well when dry and is fair when wet. It is usually solid, but it often breaks into blocky columns, so check blocks before you pull on them.

BGS record

Generic exposed scrambling terrain; BGS summit-area bedrock samples are included where available, but route grade, exact rock, polish, drainage and escape options remain unresolved. Contains British Geological Survey materials © UKRI 2026. How to use the climbing and scrambling forecast.

Did this match your experience?Tell us about the rock surface and wind to help improve this beta forecast.Give feedback

Overnight · Aurora, stars & meteorsAfter darkBetaMostly clear. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-19. All times are UK local time.

Using the last available sky forecast, updated at 03:02 BST on 19 Oct. Cloud conditions may have changed. Live aurora guidance is temporarily unavailable.

Stargazing

Good sky conditions during the best available spell: 19 Oct, 22:00 BST to 23:00 BST.

Mostly clear.

Moon-free dark sky: 20 Oct, 00:25 BST to 05:55 BST.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
19 Oct, 20:05 BST to 21:00 BST	Mixed sky conditions Some breaks in the cloud, so stars at times.
19 Oct, 21:00 BST to 22:00 BST	Good sky conditions Mostly clear.
19 Oct, 22:00 BST to 23:00 BST	Good sky conditions Mostly clear.
19 Oct, 23:00 BST to 20 Oct, 00:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
20 Oct, 00:00 BST to 01:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
20 Oct, 01:00 BST to 02:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
20 Oct, 02:00 BST to 03:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
20 Oct, 03:00 BST to 04:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
20 Oct, 04:00 BST to 05:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
20 Oct, 05:00 BST to 05:55 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.

Moon, darkness and meteor showers

Gibbous moon, about 62% illuminated.

Moonset around 20 Oct, 00:25 BST.

Full darkness: 19 Oct, 20:05 BST to 20 Oct, 05:55 BST.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 880 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit

For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.

Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part

Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.

This is about Carnedd Dafydd on Monday 19 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

About the research and your privacy · Already been out? Share that experience instead

Tuesday 20 October 2026Confidence: Medium

Overall hill weather72Good

Summit wind · 08:00-17:0010-20 mph southerly Summit gusts · 08:00-17:0015-25 mph Feels like-4 to 0°C PrecipitationAround 2-5 mm Cloud-free summit estimate90% Freezing levelAbove summit DaylightSunrise 07:50 · Sunset 18:09 · 10.3 hours daylight

The day on the hill

A good day on Carnedd Dafydd, though expect drizzle clearing by early afternoon.

Wind

On the summit expect a southerly wind of 10–20 mph for most of the day, with gusts of 15–25 mph at the windiest. Lower down on the open hillside the wind will be light, under 10 mph.

Cloud and visibility

The tops should stay clear of cloud all day.

Rain and ground

Drizzle at first, clearing by early afternoon. Expect 2–5 mm in total. Some forecast models keep it drier in the morning.

Warmth and kit

On the tops it will be around 0 to 4°C, feeling like -4 to 0°C in the wind. The freezing level is above the summits. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 6:10pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

Some of the detail could still change, so have a last look at the forecast in the morning before you set off.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 0 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 0 h
Midday: 0 h
Later: 0 h

Overnight forecast: 17:00–08:00 (UK local time), in Wild camping below.

Morning · 08:00–12:00 Mixed Summit winds around 10-20 mph. Gusts around 15-25 mph are possible on exposed ground. Rain is forecast during this period. Rain is possible during the morning, but forecast models disagree on whether it will fall.

69

Afternoon · 12:00–17:00 Good Rain eases compared with the morning. Summit winds around 10-20 mph. Gusts around 15-25 mph are possible on exposed ground. Some forecast models bring rain during the afternoon, while others keep it mostly dry.

76

Compare an early start with later conditions. The main forecast above covers the day in more detail.

Overnight · 17:00–08:00Wild campingBetaA mixed night to camp, mainly because of the rain: about 8 mm of rain. 59Mixed · 600 m View detailsHide details

Night beginning Tuesday 20 October 2026

Full overnight outlook

A mixed night to camp, mainly because of the rain. Light winds on open ground, gusting no more than about 20 mph. Dry to pitch, then about 8 mm of rain overnight and into the morning, so expect to pack a wet tent. Overnight lows of about 5°C at 900 m. A 3-season bag rated to about 4°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain7.8 mm Open ground · 600 m8 mph · gusts 16 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 72%
Moonrise: Outside this window
Moonset: 01:45 next morning BST

Clear spells may allow a view of the Moon. Illumination describes the sunlit part of the Moon, not brightness at your pitch.

Overnight window: 20 Oct, 17:00 BST to 21 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m59 · mixed

Wind / gust: 7 mph / 13 mph
Typical / low: 8.4°C / 7.5°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m59 · mixed

Wind / gust: 8 mph / 16 mph
Typical / low: 7.8°C / 6.7°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

900 m59 · mixed

Wind / gust: 9 mph / 19 mph
Typical / low: 6.5°C / 4.9°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 4°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

Open-hillside reference. A sheltered pitch may be calmer; cols and ridges may be much windier. Tent design and the exact pitch still matter. Read about sleeping-bag comfort ratings, pitching in strong winds or using the wild-camping forecast.

Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback

Daytime · exposed rockClimbing & scramblingBetaPoor conditions for exposed scrambling: wet, slippery rock. Poor27 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceWet rock likelyPeak gust15-25 mphRain2.0 mm

Main concernwet rock likely

Most common mapped rock around the summit Felsic tuff Capel Curig Volcanic Formation

Origin: Igneous
Broad rock-response group: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Summit area: Volcanic rock in 65% of 17 BGS samples within 350 m
Rock-response profile: Low confidence

View the summit BGS record

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Carneddau Ogwen

volcanic rock, slate or mudstone, sandstone or gritstone

Geological detail and BGS records

Mapped variation

8 rock types appear in the mapped samples

Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.

Summit-area sample Felsic tuff Capel Curig Volcanic Formation 306–680 m samples Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Route sample Mudstone and siltstone Cwm Eigiau Formation 767–860 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Siltstone Capel Curig Volcanic Formation 392–580 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Rhyolite Unnamed Igneous Intrusion, Ordovician Around 488 m Seen on Peak Carneddau Ogwen

Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.

BGS record

Route sample Sandstone Llewelyn Volcanic Group Around 955 m Seen on Peak Carneddau Ogwen

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.

BGS record

Route sample Volcaniclastic rock Foel Fras Volcanic Complex Around 1,048 m Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Summit-area sample Siltstone Llewelyn Volcanic Group

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Summit-area sample Microgabbro Unnamed Igneous Intrusion, Ordovician

Dolerite is a hard, dark, fine-grained rock. It grips well when dry and is fair when wet. It is usually solid, but it often breaks into blocky columns, so check blocks before you pull on them.

BGS record

Generic exposed scrambling terrain; BGS summit-area bedrock samples are included where available, but route grade, exact rock, polish, drainage and escape options remain unresolved. Contains British Geological Survey materials © UKRI 2026. How to use the climbing and scrambling forecast.

Did this match your experience?Tell us about the rock surface and wind to help improve this beta forecast.Give feedback

Overnight · Aurora, stars & meteorsAfter darkBetaSome breaks in the cloud, so stars at times. Moonlight washes out the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-20. All times are UK local time.

Using the last available sky forecast, updated at 03:02 BST on 19 Oct. Cloud conditions may have changed. Live aurora guidance is temporarily unavailable.

Stargazing

Mixed sky conditions during the best available spell: 20 Oct, 23:00 BST to 21 Oct, 00:00 BST.

Some breaks in the cloud, so stars at times. Moonlight washes out the fainter stars.

Moon-free dark sky: 21 Oct, 01:40 BST to 05:55 BST.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
20 Oct, 20:05 BST to 21:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
20 Oct, 21:00 BST to 22:00 BST	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
20 Oct, 22:00 BST to 23:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
20 Oct, 23:00 BST to 21 Oct, 00:00 BST	Mixed sky conditions Some breaks in the cloud, so stars at times. Moonlight washes out the fainter stars.
21 Oct, 00:00 BST to 01:00 BST	Mixed sky conditions Some breaks in the cloud, so stars at times.
21 Oct, 01:00 BST to 02:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
21 Oct, 02:00 BST to 03:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
21 Oct, 03:00 BST to 04:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
21 Oct, 04:00 BST to 05:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
21 Oct, 05:00 BST to 05:55 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.

Moon, darkness and meteor showers

Gibbous moon, about 72% illuminated.

Moonset around 21 Oct, 01:40 BST.

Full darkness: 20 Oct, 20:05 BST to 21 Oct, 05:55 BST.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 880 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit

For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.

Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part

Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.

This is about Carnedd Dafydd on Tuesday 20 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

About the research and your privacy · Already been out? Share that experience instead

Wednesday 21 October 2026Confidence: Medium

Overall hill weather16Poor

Summit wind · 08:00-17:0010-30 mph northwesterly Summit gusts · 08:00-17:0035-45 mph Feels like-8 to -4°C PrecipitationAround 10-20 mm Cloud-free summit estimate55% Cloud base through day700-1,800 m Freezing level900-1,200 m DaylightSunrise 07:52 · Sunset 18:07 · 10.2 hours daylight

The day on the hill

A poor day on the tops of Carnedd Dafydd, with burns likely to be in spate and sleet or snow up high.

Things to watch

Burns and rivers are likely to be in spate through much of the day and into the evening, so unbridged crossings could be difficult or impossible. Timings are rough. Turn back if a crossing looks unsafe.

Wind

On the summit expect a north-westerly wind of 10–30 mph for most of the day, with gusts of 35–45 mph at the windiest. Lower down on the open hillside it will be more like 10–20 mph. Gusts like that are strong enough to make walking into it hard work, with buffeting on ridges and edges. If the windier forecast models are right, summit gusts could reach 55–65 mph.

Cloud and visibility

The tops are likely to drift in and out of cloud, with the best chance of a clear summit in the early afternoon. The cloud base could be as low as 600–900 m around midday. A few forecast models bring it lower still, to around 400–700 m. Visibility may drop briefly in showers. Mist or fog is possible in the valleys early on, clearing by about 7am.

Rain and ground

Heavy sleet at first, clearing by mid-afternoon. Expect 10–20 mm in total, measured as melted water, so any snow would lie deeper. Totals are uncertain and could be higher.

Warmth and kit

On the tops it will be around -2 to 2°C, feeling like -8 to -4°C in the wind. The freezing level is close to summit height. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 6:05pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

It's still two days off and could change, so check again nearer the time.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 0 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 0 h
Midday: 0 h
Later: 0 h

Overnight forecast: 17:00–08:00 (UK local time), in Wild camping below.

Morning · 08:00–12:00 Poor Summit winds around 10-20 mph early in the morning, strengthening to 25-35 mph later. Gusts around 35-45 mph are possible on exposed ground. Gusts this strong can make walking into it hard work, with buffeting on ridges and edges. Summit cloud becomes more persistent later. Rain is forecast during this period. Rain is forecast during the morning, but models differ considerably on the amount.

15

Afternoon · 12:00–17:00 Poor Summit winds around 20-30 mph. Gusts around 35-45 mph are possible on exposed ground. Gusts this strong can make walking into it hard work, with buffeting on ridges and edges. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period. Rain is forecast during the afternoon, but models differ considerably on the amount.

17

Compare an early start with later conditions. The main forecast above covers the day in more detail.

Overnight · 17:00–08:00Wild campingBetaA mixed night to camp, mainly because of the wind: gusts of about 35 mph. 59Mixed · 600 m View detailsHide details

Night beginning Wednesday 21 October 2026

Full overnight outlook

A mixed night to camp, mainly because of the wind. Gusts reach about 35 mph around 900 m and nearer 25 mph around 300 m, so peg out well and use the guylines. Look for shelter from the northwest. It should stay dry. A cold night, down to about 2°C around 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain0.1 mm Open ground · 600 m12 mph · gusts 29 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 80%
Moonrise: Outside this window
Moonset: 03:03 next morning BST

Clear spells may allow a view of the Moon. Illumination describes the sunlit part of the Moon, not brightness at your pitch.

Overnight window: 21 Oct, 17:00 BST to 22 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m82 · promising

Wind / gust: 10 mph / 24 mph
Typical / low: 5.8°C / 5.4°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m59 · mixed

Wind / gust: 12 mph / 29 mph
Typical / low: 4.7°C / 4.5°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

900 m39 · poor

Wind / gust: 14 mph / 34 mph
Typical / low: 2.4°C / 1.8°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

Open-hillside reference. A sheltered pitch may be calmer; cols and ridges may be much windier. Tent design and the exact pitch still matter. Read about sleeping-bag comfort ratings, pitching in strong winds or using the wild-camping forecast.

Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback

Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 35–45 mph. Poor0 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 35–45 mph could throw you off balance on exposed moves and ridges. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceWet rock likelyPeak gust35-45 mphRain16.2 mm

Main factorsgusts of 35–45 mphwet rock likely

Most common mapped rock around the summit Felsic tuff Capel Curig Volcanic Formation

Origin: Igneous
Broad rock-response group: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Summit area: Volcanic rock in 65% of 17 BGS samples within 350 m
Rock-response profile: Low confidence

View the summit BGS record

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Carneddau Ogwen

volcanic rock, slate or mudstone, sandstone or gritstone

Geological detail and BGS records

Mapped variation

8 rock types appear in the mapped samples

Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.

Summit-area sample Felsic tuff Capel Curig Volcanic Formation 306–680 m samples Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Route sample Mudstone and siltstone Cwm Eigiau Formation 767–860 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Siltstone Capel Curig Volcanic Formation 392–580 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Rhyolite Unnamed Igneous Intrusion, Ordovician Around 488 m Seen on Peak Carneddau Ogwen

Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.

BGS record

Route sample Sandstone Llewelyn Volcanic Group Around 955 m Seen on Peak Carneddau Ogwen

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.

BGS record

Route sample Volcaniclastic rock Foel Fras Volcanic Complex Around 1,048 m Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Summit-area sample Siltstone Llewelyn Volcanic Group

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Summit-area sample Microgabbro Unnamed Igneous Intrusion, Ordovician

Dolerite is a hard, dark, fine-grained rock. It grips well when dry and is fair when wet. It is usually solid, but it often breaks into blocky columns, so check blocks before you pull on them.

BGS record

Generic exposed scrambling terrain; BGS summit-area bedrock samples are included where available, but route grade, exact rock, polish, drainage and escape options remain unresolved. Contains British Geological Survey materials © UKRI 2026. How to use the climbing and scrambling forecast.

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Overnight · Aurora, stars & meteorsAfter darkBetaMostly clear. Moonlight washes out the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-21. All times are UK local time.

Using the last available sky forecast, updated at 03:02 BST on 19 Oct. Cloud conditions may have changed. Live aurora guidance is temporarily unavailable.

Stargazing

Mixed sky conditions during the best available spell: 21 Oct, 21:00 BST to 22:00 BST.

Mostly clear. Moonlight washes out the fainter stars.

Moon-free dark sky: 22 Oct, 03:00 BST to 06:00 BST.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
21 Oct, 20:05 BST to 21:00 BST	Mixed sky conditions Some breaks in the cloud, so stars at times. Moonlight washes out the fainter stars.
21 Oct, 21:00 BST to 22:00 BST	Mixed sky conditions Mostly clear. Moonlight washes out the fainter stars.
21 Oct, 22:00 BST to 23:00 BST	Mixed sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
21 Oct, 23:00 BST to 22 Oct, 00:00 BST	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
22 Oct, 00:00 BST to 01:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
22 Oct, 01:00 BST to 02:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
22 Oct, 02:00 BST to 03:00 BST	Mixed sky conditions Forecasts disagree about rain or haze, so it could be murkier than this looks. Forecast models disagree.
22 Oct, 03:00 BST to 04:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
22 Oct, 04:00 BST to 05:00 BST	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
22 Oct, 05:00 BST to 06:00 BST	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.

Moon, darkness and meteor showers

Gibbous moon, about 80% illuminated.

Moonset around 22 Oct, 03:00 BST.

Full darkness: 21 Oct, 20:05 BST to 22 Oct, 06:00 BST.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 880 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit

For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.

Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part

Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.

This is about Carnedd Dafydd on Wednesday 21 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

About the research and your privacy · Already been out? Share that experience instead

Thursday 22 October 2026Confidence: Medium

Overall hill weather77Good

Summit wind · 08:00-17:005-20 mph westerly Summit gusts · 08:00-17:0020-30 mph Feels like-8 to -4°C PrecipitationUp to around 2 mm Cloud-free summit estimate90% Cloud base through day1,100-1,700 m Freezing level900-1,200 m DaylightSunrise 07:54 · Sunset 18:05 · 10.2 hours daylight

The day on the hill

A good day on Carnedd Dafydd, though expect sleet or snow up high.

Wind

On the summit expect a westerly wind of 5–20 mph for most of the day, with gusts of 20–30 mph at the windiest.

Cloud and visibility

The tops should stay clear of cloud all day. The air should be clear too, so expect far-reaching views from the tops.

Rain and ground

Snow is possible on the tops. Drizzle at first, clearing by mid-morning. Expect up to 2 mm in total, measured as melted water, so any snow would lie deeper. Some forecast models keep it drier in the afternoon. It will be wet underfoot after recent rain.

Warmth and kit

On the tops it will be around -2 to 2°C, feeling like -8 to -4°C in the wind. It turns milder through the day. The freezing level is close to summit height. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 6:05pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

It's still three days off and could change, so check again nearer the time.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 10 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 2 h
Midday: 4 h
Later: 2 h

Overnight forecast: 17:00–08:00 (UK local time), in Wild camping below.

Morning · 08:00–12:00 Good Summit winds around 5-15 mph. Gusts around 15-25 mph are possible on exposed ground. Summit cloud becomes more persistent later. Rain is forecast during this period.

82

Afternoon · 12:00–17:00 Good Summit winds around 10-20 mph. Gusts around 20-30 mph are possible on exposed ground. Rain is possible during the afternoon, but forecast models disagree on whether it will fall.

72

Compare an early start with later conditions. The main forecast above covers the day in more detail.

Overnight · 17:00–08:00Wild campingBetaToo windy for an exposed pitch up around 900 m (gusts of about 45 mph and around 20 mm of rain). Lower down, a poor night to camp on open ground. 39Poor · 600 m View detailsHide details

Night beginning Thursday 22 October 2026

Full overnight outlook

Too windy for an exposed pitch up around 900 m. Lower down, a poor night to camp on open ground. Gusts reach about 45 mph around 900 m and nearer 30 mph around 300 m, enough to damage a tent on open ground. Pitch low down and in real shelter, or leave it for another night. The wind swings from southwesterly to northeasterly overnight, so a pitch sheltered at dusk may not be by morning. Dry to pitch, then a wet night, around 20 mm of rain overnight and into the morning, so expect to pack a wet tent. Up around 900 m you'd likely be in cloud for part of the night: damp, and hard to find your way if you need to move. A cold night, down to about 1°C around 900 m. A warm 3-season or 3–4 season bag rated to about 0°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain19.5 mm Open ground · 600 m17 mph · gusts 38 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 0°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 88%
Moonrise: Outside this window
Moonset: 04:22 next morning BST

Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.

Overnight window: 22 Oct, 17:00 BST to 23 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m39 · poor

Wind / gust: 14 mph / 32 mph
Typical / low: 6.7°C / 4.7°C · several hours
In cloud: 0% of modelled night
Condensation: Low

600 m39 · poor

Wind / gust: 17 mph / 38 mph
Typical / low: 6.1°C / 2.7°C · several hours
In cloud: 20% of modelled night
Condensation: Low

900 m19 · very poor

Wind / gust: 20 mph / 45 mph
Typical / low: 3.5°C / 1.0°C · much of the night
In cloud: 27% of modelled night
Condensation: Moderate

Warmth planning: As a broad starting point, consider a warm 3-season or 3–4 season bag with an ISO/EN comfort rating at or below about 0°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

Open-hillside reference. A sheltered pitch may be calmer; cols and ridges may be much windier. Tent design and the exact pitch still matter. Read about sleeping-bag comfort ratings, pitching in strong winds or using the wild-camping forecast.

Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback

Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: wet, slippery rock. Poor0 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Icy patches are likely on the rock, which makes it treacherous without winter kit. Gusts of 20–30 mph will be noticeable on exposed ridges. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceWet rock likelyPeak gust20-30 mphRain0.2 mm

Main factorswet rock likelySnow may fall on high ground. Deposits could make summer scrambling conditions inappropriate

Most common mapped rock around the summit Felsic tuff Capel Curig Volcanic Formation

Origin: Igneous
Broad rock-response group: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Summit area: Volcanic rock in 65% of 17 BGS samples within 350 m
Rock-response profile: Low confidence

View the summit BGS record

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Carneddau Ogwen

volcanic rock, slate or mudstone, sandstone or gritstone

Geological detail and BGS records

Mapped variation

8 rock types appear in the mapped samples

Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.

Summit-area sample Felsic tuff Capel Curig Volcanic Formation 306–680 m samples Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Route sample Mudstone and siltstone Cwm Eigiau Formation 767–860 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Siltstone Capel Curig Volcanic Formation 392–580 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Rhyolite Unnamed Igneous Intrusion, Ordovician Around 488 m Seen on Peak Carneddau Ogwen

Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.

BGS record

Route sample Sandstone Llewelyn Volcanic Group Around 955 m Seen on Peak Carneddau Ogwen

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.

BGS record

Route sample Volcaniclastic rock Foel Fras Volcanic Complex Around 1,048 m Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Summit-area sample Siltstone Llewelyn Volcanic Group

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Summit-area sample Microgabbro Unnamed Igneous Intrusion, Ordovician

Dolerite is a hard, dark, fine-grained rock. It grips well when dry and is fair when wet. It is usually solid, but it often breaks into blocky columns, so check blocks before you pull on them.

BGS record

Generic exposed scrambling terrain; BGS summit-area bedrock samples are included where available, but route grade, exact rock, polish, drainage and escape options remain unresolved. Contains British Geological Survey materials © UKRI 2026. How to use the climbing and scrambling forecast.

Did this match your experience?Tell us about the rock surface and wind to help improve this beta forecast.Give feedback

Overnight · Aurora, stars & meteorsAfter darkBetaMostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-22. All times are UK local time.

Using the last available sky forecast, updated at 03:02 BST on 19 Oct. Cloud conditions may have changed. Live aurora guidance is temporarily unavailable.

Stargazing

Poor sky conditions during the best available spell: 22 Oct, 20:00 BST to 21:00 BST.

Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.

Moon-free dark sky: 23 Oct, 04:15 BST to 06:00 BST.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
22 Oct, 20:00 BST to 21:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
22 Oct, 21:00 BST to 22:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
22 Oct, 22:00 BST to 23:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
22 Oct, 23:00 BST to 23 Oct, 00:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
23 Oct, 00:00 BST to 01:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
23 Oct, 01:00 BST to 02:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars.
23 Oct, 02:00 BST to 03:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars.
23 Oct, 03:00 BST to 04:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.
23 Oct, 04:00 BST to 05:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.
23 Oct, 05:00 BST to 06:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.

Moon, darkness and meteor showers

Gibbous moon, about 88% illuminated.

Moonset around 23 Oct, 04:15 BST.

Full darkness: 22 Oct, 20:00 BST to 23 Oct, 06:00 BST.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 880 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit

For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.

Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part

Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.

This is about Carnedd Dafydd on Thursday 22 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

About the research and your privacy · Already been out? Share that experience instead

Friday 23 October 2026Confidence: Medium

Overall hill weather0Poor

Summit wind · 08:00-17:0030-40 mph northerly Summit gusts · 08:00-17:0045-55 mph Feels like-10 to -6°C PrecipitationAround 10-20 mm Cloud-free summit estimate70% Cloud base through day900-1,800 m Freezing level1,000-1,300 m DaylightSunrise 07:56 · Sunset 18:03 · 10.1 hours daylight

The day on the hill

A poor day on the tops of Carnedd Dafydd, with burns in severe spate and strong, gusty winds.

Things to watch

Burns and rivers are likely to be in severe spate through much of the day and into the night. Do not attempt unbridged crossings. Timings are rough. Turn back if a crossing looks unsafe.

Wind

On the summit expect a northerly wind of 30–40 mph for most of the day, with gusts of 45–55 mph at the windiest. Lower down on the open hillside it will be more like 15–25 mph. Gusts like that are strong enough to knock you off balance, so take care near edges and on narrow ridges. If the windier forecast models are right, summit gusts could reach 60–70 mph.

Cloud and visibility

The tops are likely to drift in and out of cloud, with the best chance of a clear summit mid-morning. The cloud base could be as low as 600–900 m early in the morning. A few forecast models bring it lower still, to around 300–600 m. Visibility may drop briefly in showers. It will look largely cloudy overhead, but that cloud should mostly stay above the tops.

Rain and ground

Heavy sleet at first, clearing by mid-afternoon. Expect 10–20 mm in total, measured as melted water, so any snow would lie deeper. Totals are uncertain and could be higher. It will be wet underfoot after recent rain.

Warmth and kit

On the tops it will be around -2 to 2°C, feeling like -10 to -6°C in the wind. The freezing level is close to summit height. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 6:05pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

There is some disagreement between forecast models on wind strength. It's still four days off and could change, so check again nearer the time.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 0 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 0 h
Midday: 0 h
Later: 0 h

Overnight forecast: 17:00–08:00 (UK local time), in Wild camping below.

Morning · 08:00–12:00 Severe hill conditions Summit winds around 30-40 mph. Gusts around 45-55 mph are possible on exposed ground. Gusts this strong can knock you off balance, so take care near edges and on narrow ridges. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period. Rain is forecast during the morning, but models differ considerably on the amount.

-18

Afternoon · 12:00–17:00 Poor Summit winds around 30-40 mph. Gusts around 45-55 mph are possible on exposed ground. Gusts this strong can knock you off balance, so take care near edges and on narrow ridges. Rain is forecast during this period. Rain is possible during the afternoon, but forecast models disagree on whether it will fall.

18

Compare an early start with later conditions. The main forecast above covers the day in more detail.

Overnight · 17:00–08:00Wild campingBetaToo windy for an exposed pitch up around 900 m (gusts of about 45 mph). Lower down, a mixed night to camp, mainly because of the wind. 39Poor · 600 m View detailsHide details

Night beginning Friday 23 October 2026

Full overnight outlook

Too windy for an exposed pitch up around 900 m. Lower down, a mixed night to camp, mainly because of the wind. Gusts reach about 45 mph around 900 m and nearer 30 mph around 300 m, which makes for a noisy, testing night even in a good tent. Pitch low down and in real shelter, or leave it for another night. The wind swings from northwesterly to southwesterly overnight, so a pitch sheltered at dusk may not be by morning. Dry to pitch, then a little rain by morning, so you'll likely pack up in the wet. A cold night, down to about 2°C around 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain0.4 mm Open ground · 600 m21 mph · gusts 38 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 94%
Moonrise: Outside this window
Moonset: 05:43 next morning BST

Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.

Overnight window: 23 Oct, 17:00 BST to 24 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m59 · mixed

Wind / gust: 17 mph / 31 mph
Typical / low: 5.4°C / 5.2°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m39 · poor

Wind / gust: 21 mph / 38 mph
Typical / low: 4.6°C / 4.4°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

900 m19 · very poor

Wind / gust: 25 mph / 44 mph
Typical / low: 2.0°C / 1.5°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

Open-hillside reference. A sheltered pitch may be calmer; cols and ridges may be much windier. Tent design and the exact pitch still matter. Read about sleeping-bag comfort ratings, pitching in strong winds or using the wild-camping forecast.

Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback

Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: wet, slippery rock. Poor0 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Snow is likely on the rock and ledges, so it becomes a winter route. Gusts of 45–55 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceWet rock likelyPeak gust45-55 mphRain15.0 mm

Main factorsgusts of 45–55 mphwet rock likelySnow is likely to be lying on high ground. Scrambling may require winter mountaineering skills and equipment

Most common mapped rock around the summit Felsic tuff Capel Curig Volcanic Formation

Origin: Igneous
Broad rock-response group: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Summit area: Volcanic rock in 65% of 17 BGS samples within 350 m
Rock-response profile: Low confidence

View the summit BGS record

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Carneddau Ogwen

volcanic rock, slate or mudstone, sandstone or gritstone

Geological detail and BGS records

Mapped variation

8 rock types appear in the mapped samples

Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.

Summit-area sample Felsic tuff Capel Curig Volcanic Formation 306–680 m samples Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Route sample Mudstone and siltstone Cwm Eigiau Formation 767–860 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Siltstone Capel Curig Volcanic Formation 392–580 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Rhyolite Unnamed Igneous Intrusion, Ordovician Around 488 m Seen on Peak Carneddau Ogwen

Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.

BGS record

Route sample Sandstone Llewelyn Volcanic Group Around 955 m Seen on Peak Carneddau Ogwen

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.

BGS record

Route sample Volcaniclastic rock Foel Fras Volcanic Complex Around 1,048 m Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Summit-area sample Siltstone Llewelyn Volcanic Group

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Summit-area sample Microgabbro Unnamed Igneous Intrusion, Ordovician

Dolerite is a hard, dark, fine-grained rock. It grips well when dry and is fair when wet. It is usually solid, but it often breaks into blocky columns, so check blocks before you pull on them.

BGS record

Generic exposed scrambling terrain; BGS summit-area bedrock samples are included where available, but route grade, exact rock, polish, drainage and escape options remain unresolved. Contains British Geological Survey materials © UKRI 2026. How to use the climbing and scrambling forecast.

Did this match your experience?Tell us about the rock surface and wind to help improve this beta forecast.Give feedback

Overnight · Aurora, stars & meteorsAfter darkBetaSome forecasts show clear spells, others keep it cloudy; check again nearer the time. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-23. All times are UK local time.

Using the last available sky forecast, updated at 03:02 BST on 19 Oct. Cloud conditions may have changed. Live aurora guidance is temporarily unavailable.

Stargazing

Mixed sky conditions during the best available spell: 24 Oct, 05:00 BST to 06:00 BST.

Some forecasts show clear spells, others keep it cloudy; check again nearer the time.

Moon-free dark sky: 24 Oct, 05:35 BST to 06:05 BST.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
23 Oct, 20:00 BST to 21:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
23 Oct, 21:00 BST to 22:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
23 Oct, 22:00 BST to 23:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
23 Oct, 23:00 BST to 24 Oct, 00:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
24 Oct, 00:00 BST to 01:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
24 Oct, 01:00 BST to 02:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
24 Oct, 02:00 BST to 03:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
24 Oct, 03:00 BST to 04:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
24 Oct, 04:00 BST to 05:00 BST	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
24 Oct, 05:00 BST to 06:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
24 Oct, 06:00 BST to 06:05 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.

Moon, darkness and meteor showers

Gibbous moon, about 94% illuminated.

Moonset around 24 Oct, 05:35 BST.

Full darkness: 23 Oct, 20:00 BST to 24 Oct, 06:05 BST.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 880 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit

For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.

Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part

Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.

This is about Carnedd Dafydd on Friday 23 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

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Saturday 24 October 2026Confidence: Unavailable

Overall hill weather32Poor

Summit wind · 08:00-17:0025-45 mph southwesterly Summit gusts · 08:00-17:0055-65 mph Feels like-6 to -2°C PrecipitationAround 5-10 mm Cloud-free summit estimate50% Cloud base through day600-1,500 m Freezing levelAbove summit DaylightSunrise 07:58 · Sunset 18:01 · 10.1 hours daylight

The day on the hill

A poor day on the tops of Carnedd Dafydd, with very strong, gusty winds and rain for much of the day.

Wind

On the summit expect a south-westerly wind of 25–45 mph for most of the day, with gusts of 55–65 mph at the windiest. Lower down on the open hillside it will be more like 10–20 mph. Gusts like that are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. If the windier forecast models are right, summit gusts could reach 80–90 mph.

Cloud and visibility

The tops should stay mostly clear of cloud. The cloud base could be as low as 600–900 m in the late afternoon. A few forecast models bring it lower still, to around 300–600 m. Visibility may drop briefly in showers.

Rain and ground

Rain for much of the day. Expect 5–10 mm in total. Some forecast models keep it drier in the afternoon. The ground is very wet after recent rain, so expect boggy paths.

Warmth and kit

On the tops it will be around 0 to 4°C, feeling like -6 to -2°C in the wind. It turns milder through the day. The freezing level is above the summits. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 6pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

It's still five days off and could change, so check again nearer the time.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 0 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 0 h
Midday: 0 h
Later: 0 h

Overnight forecast: 17:00–08:00 (UK local time), in Wild camping below.

Morning · 08:00–12:00 Poor Summit winds around 25-35 mph early in the morning, strengthening to 30-40 mph later. Gusts around 45-55 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period.

42

Afternoon · 12:00–17:00 Poor Winds strengthen compared with the morning. Summit winds around 30-45 mph. Gusts around 55-65 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period. Some forecast models bring rain during the afternoon, while others keep it mostly dry.

21

Compare an early start with later conditions. The main forecast above covers the day in more detail.

Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 60 mph and about 7 mm of rain. 9Poor · 600 m View detailsHide details

Night beginning Saturday 24 October 2026

Full overnight outlook

Not a night to camp on the open hill. Gusts reach about 60 mph around 900 m and nearer 45 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. Expect about 7 mm of rain, with rain while you pitch and still falling when you pack up. Up around 900 m you'd likely be in cloud for part of the night: damp, and hard to find your way if you need to move. A cold night, down to about 2°C around 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold. The ground will be sodden after recent rain, so pick a firm, well-drained pitch.

Overnight rain7.2 mm Open ground · 600 m29 mph · gusts 51 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Near-full moon

Illuminated disc: 98%
Moonrise: Outside this window
Moonset: 06:09 next morning GMT

Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.

Overnight window: 24 Oct, 17:00 BST to 25 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m19 · very poor

Wind / gust: 24 mph / 43 mph
Typical / low: 7.7°C / 5.5°C · much of the night
In cloud: 0% of modelled night
Condensation: Moderate

600 m9 · very poor

Wind / gust: 29 mph / 51 mph
Typical / low: 7.2°C / 4.9°C · a brief spell
In cloud: 19% of modelled night
Condensation: High

900 m0 · very poor

Wind / gust: 34 mph / 60 mph
Typical / low: 4.9°C / 2.3°C · several hours
In cloud: 38% of modelled night
Condensation: High

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

The ground is likely to be very wet after recent rain. Expect boggy approaches and choose a durable pitch carefully.

Open-hillside reference. A sheltered pitch may be calmer; cols and ridges may be much windier. Tent design and the exact pitch still matter. Read about sleeping-bag comfort ratings, pitching in strong winds or using the wild-camping forecast.

Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback

Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 55–65 mph. Poor0 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 55–65 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceWet rock likelyPeak gust55-65 mphRain5.0 mm

Main factorsgusts of 55–65 mphwet rock likely

Most common mapped rock around the summit Felsic tuff Capel Curig Volcanic Formation

Origin: Igneous
Broad rock-response group: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Summit area: Volcanic rock in 65% of 17 BGS samples within 350 m
Rock-response profile: Low confidence

View the summit BGS record

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Carneddau Ogwen

volcanic rock, slate or mudstone, sandstone or gritstone

Geological detail and BGS records

Mapped variation

8 rock types appear in the mapped samples

Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.

Summit-area sample Felsic tuff Capel Curig Volcanic Formation 306–680 m samples Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Route sample Mudstone and siltstone Cwm Eigiau Formation 767–860 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Siltstone Capel Curig Volcanic Formation 392–580 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Rhyolite Unnamed Igneous Intrusion, Ordovician Around 488 m Seen on Peak Carneddau Ogwen

Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.

BGS record

Route sample Sandstone Llewelyn Volcanic Group Around 955 m Seen on Peak Carneddau Ogwen

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.

BGS record

Route sample Volcaniclastic rock Foel Fras Volcanic Complex Around 1,048 m Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Summit-area sample Siltstone Llewelyn Volcanic Group

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Summit-area sample Microgabbro Unnamed Igneous Intrusion, Ordovician

Dolerite is a hard, dark, fine-grained rock. It grips well when dry and is fair when wet. It is usually solid, but it often breaks into blocky columns, so check blocks before you pull on them.

BGS record

Generic exposed scrambling terrain; BGS summit-area bedrock samples are included where available, but route grade, exact rock, polish, drainage and escape options remain unresolved. Contains British Geological Survey materials © UKRI 2026. How to use the climbing and scrambling forecast.

Did this match your experience?Tell us about the rock surface and wind to help improve this beta forecast.Give feedback

Overnight · Aurora, stars & meteorsAfter darkBetaSome breaks in the cloud, so stars at times. Moonlight washes out the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-24. All times are UK local time.

Using the last available sky forecast, updated at 03:02 BST on 19 Oct. Cloud conditions may have changed. Live aurora guidance is temporarily unavailable.

Stargazing

Mixed sky conditions during the best available spell: 25 Oct, 04:00 GMT to 05:00 GMT.

Some breaks in the cloud, so stars at times. Moonlight washes out the fainter stars.

A bright moon is up all through the dark hours, washing out fainter stars and meteors.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
24 Oct, 19:55 BST to 20:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
24 Oct, 20:00 BST to 21:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
24 Oct, 21:00 BST to 22:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
24 Oct, 22:00 BST to 23:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
24 Oct, 23:00 BST to 25 Oct, 00:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
25 Oct, 00:00 BST to 01:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars.
25 Oct, 01:00 GMT to 02:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars. Limited model coverage.
25 Oct, 01:00 BST to 01:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars. Limited model coverage.
25 Oct, 02:00 GMT to 03:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars. Limited model coverage.
25 Oct, 03:00 GMT to 04:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars. Limited model coverage.
25 Oct, 04:00 GMT to 05:00 GMT	Mixed sky conditions Some breaks in the cloud, so stars at times. Moonlight washes out the fainter stars. Limited model coverage.
25 Oct, 05:00 GMT to 05:05 GMT	Mixed sky conditions Some breaks in the cloud, so stars at times. Moonlight washes out the fainter stars. Limited model coverage.

Moon, darkness and meteor showers

Near-full moon, about 98% illuminated.

Moonset around 25 Oct, 06:00 GMT.

Full darkness: 24 Oct, 19:55 BST to 25 Oct, 05:05 GMT.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 880 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit

For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.

Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part

Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.

This is about Carnedd Dafydd on Saturday 24 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

About the research and your privacy · Already been out? Share that experience instead

Sunday 25 October 2026Confidence: Unavailable

Overall hill weather18Poor

Summit wind · 08:00-17:0040-50 mph westerly Summit gusts · 08:00-17:0055-65 mph Feels like-10 to -6°C PrecipitationAround 2-5 mm Cloud-free summit estimate90% Freezing level1,100-1,400 m DaylightSunrise 07:00 · Sunset 16:59 · 10.0 hours daylight

The day on the hill

A poor day on the tops of Carnedd Dafydd, with very strong, gusty winds and sleet or snow up high.

Wind

On the summit expect a westerly wind of 40–50 mph for most of the day, with gusts of 55–65 mph at the windiest. Lower down on the open hillside it will be more like 10–20 mph. Gusts like that are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. If the windier forecast models are right, summit gusts could reach 80–90 mph.

Cloud and visibility

The tops should stay clear of cloud all day.

Rain and ground

Sleet is possible on the tops, and it could turn to snow if it is a little colder. Drizzle for much of the day. Expect 2–5 mm in total, measured as melted water, so any snow would lie deeper. It will be wet underfoot after recent rain.

Warmth and kit

On the tops it will be around 0 to 4°C, feeling like -10 to -6°C in the wind. The freezing level is close to summit height. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 5pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

It's still six days off and could change, so check again nearer the time.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 8.9 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 2 h
Midday: 4 h
Later: 0.9 h

Overnight forecast: 17:00–08:00 (UK local time), in Wild camping below.

Morning · 08:00–12:00 Poor Summit winds around 40-50 mph. Gusts around 55-65 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period.

12

Afternoon · 12:00–17:00 Poor Summit winds around 40-50 mph. Gusts around 55-65 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period.

25

Compare an early start with later conditions. The main forecast above covers the day in more detail.

Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 55 mph and about 7 mm of rain. 9Poor · 600 m View detailsHide details

Night beginning Sunday 25 October 2026

Full overnight outlook

Not a night to camp on the open hill. Gusts reach about 55 mph around 900 m and nearer 40 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. Expect about 7 mm of rain, with rain while you pitch and still falling when you pack up. A cold night, down to about 1°C around 900 m. A warm 3-season or 3–4 season bag rated to about 0°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain6.9 mm Open ground · 600 m33 mph · gusts 49 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 0°C or lower

Moon overnight

Near-full moon

Illuminated disc: 100%
Moonrise: Outside this window
Moonset: 07:39 next morning GMT

Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.

Overnight window: 25 Oct, 17:00 GMT to 26 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m19 · very poor

Wind / gust: 27 mph / 40 mph
Typical / low: 4.0°C / 3.7°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m9 · very poor

Wind / gust: 33 mph / 49 mph
Typical / low: 4.0°C / 3.7°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

900 m9 · very poor

Wind / gust: 39 mph / 57 mph
Typical / low: 1.7°C / 1.2°C · much of the night
In cloud: 0% of modelled night
Condensation: Moderate

Warmth planning: As a broad starting point, consider a warm 3-season or 3–4 season bag with an ISO/EN comfort rating at or below about 0°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

Open-hillside reference. A sheltered pitch may be calmer; cols and ridges may be much windier. Tent design and the exact pitch still matter. Read about sleeping-bag comfort ratings, pitching in strong winds or using the wild-camping forecast.

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Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 55–65 mph. Poor0 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 55–65 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceWet rock likelyPeak gust55-65 mphRain5.9 mm

Main factorsgusts of 55–65 mphwet rock likely

Most common mapped rock around the summit Felsic tuff Capel Curig Volcanic Formation

Origin: Igneous
Broad rock-response group: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Summit area: Volcanic rock in 65% of 17 BGS samples within 350 m
Rock-response profile: Low confidence

View the summit BGS record

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Carneddau Ogwen

volcanic rock, slate or mudstone, sandstone or gritstone

Geological detail and BGS records

Mapped variation

8 rock types appear in the mapped samples

Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.

Summit-area sample Felsic tuff Capel Curig Volcanic Formation 306–680 m samples Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Route sample Mudstone and siltstone Cwm Eigiau Formation 767–860 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Siltstone Capel Curig Volcanic Formation 392–580 m samples Seen on Peak Carneddau Ogwen

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Route sample Rhyolite Unnamed Igneous Intrusion, Ordovician Around 488 m Seen on Peak Carneddau Ogwen

Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.

BGS record

Route sample Sandstone Llewelyn Volcanic Group Around 955 m Seen on Peak Carneddau Ogwen

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.

BGS record

Route sample Volcaniclastic rock Foel Fras Volcanic Complex Around 1,048 m Seen on Peak Carneddau Ogwen

Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.

BGS record

Summit-area sample Siltstone Llewelyn Volcanic Group

Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.

BGS record

Summit-area sample Microgabbro Unnamed Igneous Intrusion, Ordovician

Dolerite is a hard, dark, fine-grained rock. It grips well when dry and is fair when wet. It is usually solid, but it often breaks into blocky columns, so check blocks before you pull on them.

BGS record

Generic exposed scrambling terrain; BGS summit-area bedrock samples are included where available, but route grade, exact rock, polish, drainage and escape options remain unresolved. Contains British Geological Survey materials © UKRI 2026. How to use the climbing and scrambling forecast.

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Overnight · Aurora, stars & meteorsAfter darkBetaSome breaks in the cloud, so stars at times. Rain at times. Moonlight washes out the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-25. All times are UK local time.

Using the last available sky forecast, updated at 03:02 BST on 19 Oct. Cloud conditions may have changed. Live aurora guidance is temporarily unavailable.

Stargazing

Poor sky conditions during the best available spell: 25 Oct, 23:00 GMT to 26 Oct, 00:00 GMT.

Some breaks in the cloud, so stars at times. Rain at times. Moonlight washes out the fainter stars.

A bright moon is up all through the dark hours, washing out fainter stars and meteors.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
25 Oct, 18:55 GMT to 19:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars. Limited model coverage.
25 Oct, 19:00 GMT to 20:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
25 Oct, 20:00 GMT to 21:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
25 Oct, 21:00 GMT to 22:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
25 Oct, 22:00 GMT to 23:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
25 Oct, 23:00 GMT to 26 Oct, 00:00 GMT	Poor sky conditions Some breaks in the cloud, so stars at times. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 00:00 GMT to 01:00 GMT	Poor sky conditions Some breaks in the cloud, so stars at times. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 01:00 GMT to 02:00 GMT	Poor sky conditions Some breaks in the cloud, so stars at times. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 02:00 GMT to 03:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 03:00 GMT to 04:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 04:00 GMT to 05:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 05:00 GMT to 05:05 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars. Limited model coverage.

Moon, darkness and meteor showers

Near-full moon, about 100% illuminated.

Moonset around 26 Oct, 07:25 GMT.

Full darkness: 25 Oct, 18:55 GMT to 26 Oct, 05:05 GMT.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 880 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit

For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.

Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part

Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.

This is about Carnedd Dafydd on Sunday 25 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

About the research and your privacy · Already been out? Share that experience instead

Carnedd Dafydd weather forecast.

Choose your hill day.

The day on the hill

Wind

Cloud and visibility

Rain and ground

Warmth and kit

Daylight

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Carneddau Ogwen

8 rock types appear in the mapped samples

After dark: aurora and stargazing

Stargazing

Darkness of the surroundings

The day on the hill

Wind

Cloud and visibility

Rain and ground

Warmth and kit

Daylight

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Carneddau Ogwen

8 rock types appear in the mapped samples

After dark: aurora and stargazing

Stargazing

Darkness of the surroundings

The day on the hill

Things to watch

Wind

Cloud and visibility

Rain and ground

Warmth and kit

Daylight

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Carneddau Ogwen

8 rock types appear in the mapped samples

After dark: aurora and stargazing

Stargazing

Darkness of the surroundings

The day on the hill

Wind

Cloud and visibility

Rain and ground

Warmth and kit

Daylight

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Carneddau Ogwen

8 rock types appear in the mapped samples

After dark: aurora and stargazing

Stargazing

Darkness of the surroundings

The day on the hill

Things to watch

Wind

Cloud and visibility

Rain and ground

Warmth and kit

Daylight

Forecast confidence

Full overnight outlook