Y Llethr Weather Forecast – 756m, Eryri (Snowdonia)

Thursday 5 November 2026Confidence: Medium

Overall hill weather66Mixed

Summit wind · 08:00-17:0015-30 mph easterly Summit gusts · 08:00-17:0035-45 mph Feels like-6 to -2°C PrecipitationLittle or none Cloud-free summit estimate85% Cloud base through day700-1,500 m Freezing levelAbove summit DaylightSunrise 07:19 · Sunset 16:38 · 9.3 hours daylight

The day on the hill

A mixed day on Y Llethr, with a blustery wind.

Wind

On the summit expect an easterly wind of 15–30 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.

Cloud and visibility

The tops should stay mostly clear of cloud. A few forecast models bring the cloud base down to around 600–900 m at times. The cloud base sits close to summit height, so the top could go in and out of cloud at short notice. The air should be clear, so expect far-reaching views as long as the tops stay clear.

Rain and ground

It should stay dry.

Warmth and kit

On the tops it will be around 2 to 6°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 4:40pm, 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 3.3 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: 1 h
Midday: 1.3 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 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.

60

Afternoon · 12:00–17:00 Good Summit winds around 15-30 mph. Gusts around 30-40 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.

71

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 cold: gusts of about 25 mph. 59Mixed · 600 m View detailsHide details

Night beginning Thursday 5 November 2026

Full overnight outlook

A mixed night to camp, mainly because of the cold. Gusts reach about 25 mph on open ground, so peg out well and use the guylines. Look for shelter from the east. It should stay dry. Overnight lows of about 3°C at 300 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 rain0.0 mm Open ground · 600 m16 mph · gusts 25 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 0°C or lower

Moon overnight

Waning crescent moon

Illuminated disc: 11%
Moonrise: 04:08 next morning GMT
Moonset: Outside this window

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

Overnight window: 5 Nov, 17:00 GMT to 6 Nov, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m59 · mixed

Wind / gust: 13 mph / 21 mph
Typical / low: 3.9°C / 3.4°C · much of the night
In cloud: 0% of modelled night
Condensation: Moderate

600 m59 · mixed

Wind / gust: 16 mph / 25 mph
Typical / low: 3.9°C / 3.4°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.

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

Daytime · exposed rockClimbing & scramblingBetaFair conditions for exposed scrambling: gusts of 35–45 mph. Mixed69 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Fair conditions for exposed scrambling. The rock should be mostly dry, though drainage lines and shaded holds may still be damp. Gusts of 35–45 mph could throw you off balance on exposed moves and ridges. The rock around the summit is mostly mudstone or slate, 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. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceProbably dryPeak gust35-45 mphRain0.0 mm

Main concerngusts of 35–45 mph

Representative rock around the summit Mudstone Hafotty Formation

Origin: Sedimentary
Broad rock-response group: Slate or mudstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Slate or mudstone in 71% of 17 BGS samples within 350 m
Rock-response profile: Moderate confidence

View the summit BGS record

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. 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.

Geological detail and BGS records

Mapped variation

3 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 Mudstone Hafotty Formation

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 Sandstone Hafotty Formation

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

Summit-area sample Sandstone and mudstone Rhinog Formation

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

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 2026-11-05. All times are UK local time.

Aurora is unlikely on this night

Too quiet for a likely sighting from here. Activity peaks around Kp 2.3 (on a 0 to 9 scale). It would take about Kp 5.7 for a camera to pick up a glow low in the north, though that is not a hard line. NOAA has a G1 storm watch out for this date, though the timing of the strongest activity can shift.

Activity can change at short notice. Check again on the night.

Stargazing

Mixed sky conditions during the best available spell: 5 Nov, 22:00 GMT to 23:00 GMT.

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

Moon-free dark sky: 5 Nov, 18:35 GMT to 6 Nov, 04:15 GMT.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
5 Nov, 18:35 GMT to 19:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
5 Nov, 19:00 GMT to 20:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
5 Nov, 20:00 GMT to 21:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
5 Nov, 21:00 GMT to 22:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
5 Nov, 22:00 GMT to 23:00 GMT	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
5 Nov, 23:00 GMT to 6 Nov, 00:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
6 Nov, 00:00 GMT to 01:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
6 Nov, 01:00 GMT to 02:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
6 Nov, 02:00 GMT to 03:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
6 Nov, 03:00 GMT to 04:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
6 Nov, 04:00 GMT to 05:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
6 Nov, 05:00 GMT to 05:25 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.

Moon, darkness and meteor showers

Crescent moon, about 10% illuminated.

Moonrise around 6 Nov, 04:15 GMT.

Full darkness: 5 Nov, 18:35 GMT to 6 Nov, 05:25 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.

Leonids 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 473 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 Y Llethr on Thursday 5 November 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 6 November 2026Confidence: Medium

Overall hill weather86Excellent

Summit wind · 08:00-17:005-20 mph southeasterly Summit gusts · 08:00-17:0015-25 mph Feels like-4 to 0°C PrecipitationLittle or none Cloud-free summit estimate85% Freezing levelAbove summit DaylightSunrise 07:21 · Sunset 16:36 · 9.2 hours daylight

The day on the hill

A fine day on Y Llethr: dry, with light winds and clear tops for most of the day.

Wind

On the summit expect a south-easterly wind of 5–20 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 are likely to stay mostly clear of cloud, though brief patches cannot be ruled out.

Rain and ground

Mostly dry, but some forecast models bring rain in the morning.

Warmth and kit

On the tops it will be around 2 to 6°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.

Daylight

Sunset is around 4:35pm, 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 4.7 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: 1.7 h
Midday: 3 h
Later: 0 h

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

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

82

Afternoon · 12:00–17:00 Excellent Summit winds around 5-15 mph. Gusts around 10-20 mph are possible on exposed ground.

90

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

Overnight · 17:00–08:00Wild campingBetaA very good night for a wild camp: dry, with light winds. 91Excellent · 600 m View detailsHide details

Night beginning Friday 6 November 2026

Full overnight outlook

A very good night for a wild camp. Light winds on open ground, gusting no more than about 11 mph. It should stay dry. Overnight lows of about 6°C at 300 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain0.0 mm Open ground · 600 m5 mph · gusts 11 mph Morning pack-upNo wet signal Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Waning crescent moon

Illuminated disc: 5%
Moonrise: 05:26 next morning GMT
Moonset: Outside this window

Cloud may affect views of the Moon. Illumination describes the sunlit part of the Moon, not brightness at your pitch.

Overnight window: 6 Nov, 17:00 GMT to 7 Nov, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m91 · very good

Wind / gust: 4 mph / 10 mph
Typical / low: 5.9°C / 5.6°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m91 · very good

Wind / gust: 5 mph / 11 mph
Typical / low: 5.9°C / 5.6°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 & scramblingBetaGood conditions for exposed scrambling. Good82 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Good conditions for exposed scrambling. It should stay mostly dry, but a passing shower could leave the rock damp and slippery. The rock around the summit is mostly mudstone or slate, 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. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceDry initially; rain possiblePeak gust15-25 mphRainPossible · 42%

Main concernrain possible despite mostly dry conditions being favoured

Representative rock around the summit Mudstone Hafotty Formation

Origin: Sedimentary
Broad rock-response group: Slate or mudstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Slate or mudstone in 71% of 17 BGS samples within 350 m
Rock-response profile: Moderate confidence

View the summit BGS record

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. 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.

Geological detail and BGS records

Mapped variation

3 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 Mudstone Hafotty Formation

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 Sandstone Hafotty Formation

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

Summit-area sample Sandstone and mudstone Rhinog Formation

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

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. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-11-06. All times are UK local time.

A noticeable aurora display is unlikely; any glow may be faint or camera-only

A noticeable aurora display is unlikely here. Any glow may be faint or camera-only. Activity peaks around Kp 5.0 (on a 0 to 9 scale). NOAA has a G1 storm watch out for this date, though the timing of the strongest activity can shift.

Activity can change at short notice. Check again on the night.

Stargazing

Good sky conditions during the best available spell: 6 Nov, 22:00 GMT to 23:00 GMT.

Some breaks in the cloud, so stars at times.

Moon-free dark sky: 6 Nov, 18:35 GMT to 7 Nov, 05:25 GMT.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
6 Nov, 18:35 GMT to 19:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
6 Nov, 19:00 GMT to 20:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
6 Nov, 20:00 GMT to 21:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
6 Nov, 21:00 GMT to 22:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
6 Nov, 22:00 GMT to 23:00 GMT	Good sky conditions Some breaks in the cloud, so stars at times.
6 Nov, 23:00 GMT to 7 Nov, 00:00 GMT	Mixed sky conditions Some breaks in the cloud, so stars at times.
7 Nov, 00:00 GMT to 01:00 GMT	Mixed sky conditions Mostly cloudy, so little chance of seeing the stars.
7 Nov, 01:00 GMT to 02:00 GMT	Mixed sky conditions Mostly cloudy, so little chance of seeing the stars.
7 Nov, 02:00 GMT to 03:00 GMT	Mixed sky conditions Mostly cloudy, so little chance of seeing the stars.
7 Nov, 03:00 GMT to 04:00 GMT	Poor sky conditions Forecasts disagree about rain or haze, so it could be murkier than this looks. Forecast models disagree.
7 Nov, 04:00 GMT to 05:00 GMT	Poor sky conditions Forecasts disagree about rain or haze, so it could be murkier than this looks. Forecast models disagree.
7 Nov, 05:00 GMT to 05:25 GMT	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

Near-new moon, about 5% illuminated.

Moonrise around 7 Nov, 05:40 GMT.

Full darkness: 6 Nov, 18:35 GMT to 7 Nov, 05:25 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.

Leonids 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 473 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 Y Llethr on Friday 6 November 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

Saturday 7 November 2026Confidence: Medium

Overall hill weather90Excellent

Summit wind · 08:00-17:000-10 mph northwesterly Summit gusts · 08:00-17:005-15 mph Feels like-4 to 0°C PrecipitationLittle or none Cloud-free summit estimate85% Cloud base through day600-1,400 m Freezing levelAbove summit DaylightSunrise 07:23 · Sunset 16:34 · 9.2 hours daylight

The day on the hill

A fine day on Y Llethr: dry, with light winds and clear tops for most of the day.

Wind

On the summit expect light winds of up to 10 mph, mainly north-westerly, with gusts of 5–15 mph at the windiest.

Cloud and visibility

The tops should stay mostly clear of cloud. The cloud base could be as low as 600–900 m mid-afternoon. Patchy mist is possible in sheltered valleys early on. Good spells of sunshine are likely. The air should be clear, so expect far-reaching views as long as the tops stay clear.

Rain and ground

It should stay dry.

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.

Daylight

Sunset is around 4:35pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

Cloud height is hard to pin down, so the summit could be in or out of cloud at short notice. 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 6.9 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: 3.8 h
Later: 0 h

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

Morning · 08:00–12:00 Excellent Summit winds around 0-10 mph. Gusts around 5-15 mph are possible on exposed ground.

90

Afternoon · 12:00–17:00 Excellent Summit winds around 0-10 mph. Gusts around 5-15 mph are possible on exposed ground. Summit cloud becomes more persistent later.

89

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 damp air: gusts of about 10 mph. 54Mixed · 600 m View detailsHide details

Night beginning Saturday 7 November 2026

Full overnight outlook

A mixed night to camp, mainly because of damp air. Light winds on open ground, gusting no more than about 10 mph. Dry to pitch, then a little rain overnight, easing by morning, though the tent may still be wet. Up around 600 m you'd likely be in cloud for part of the night: damp, and hard to find your way if you need to move. The air is damp at every height we checked (300-600 m), so expect heavy condensation. Leave the vents open. Overnight lows of about 4°C at 300 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain0.6 mm Open ground · 600 m5 mph · gusts 10 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Near-new moon

Illuminated disc: 2%
Moonrise: 06:45 next morning GMT
Moonset: Outside this window

Cloud may affect views of the Moon. Illumination describes the sunlit part of the Moon, not brightness at your pitch.

Overnight window: 7 Nov, 17:00 GMT to 8 Nov, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m59 · mixed

Wind / gust: 4 mph / 8 mph
Typical / low: 4.8°C / 4.5°C · much of the night
In cloud: 0% of modelled night
Condensation: High

600 m54 · mixed

Wind / gust: 5 mph / 10 mph
Typical / low: 4.6°C / 4.5°C · much of the night
In cloud: 60% 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.

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 & scramblingBetaExcellent conditions for exposed scrambling. Excellent92 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Excellent conditions for exposed scrambling. The rock should be mostly dry, though drainage lines and shaded holds may still be damp. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly mudstone or slate, 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. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceProbably dryPeak gust5-15 mphRain0.0 mm

Representative rock around the summit Mudstone Hafotty Formation

Origin: Sedimentary
Broad rock-response group: Slate or mudstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Slate or mudstone in 71% of 17 BGS samples within 350 m
Rock-response profile: Moderate confidence

View the summit BGS record

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. 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.

Geological detail and BGS records

Mapped variation

3 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 Mudstone Hafotty Formation

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 Sandstone Hafotty Formation

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

Summit-area sample Sandstone and mudstone Rhinog Formation

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

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 2026-11-07. All times are UK local time.

Aurora is unlikely on this night

A noticeable aurora display is unlikely here. Any glow may be faint or camera-only. Activity peaks around Kp 4.0 (on a 0 to 9 scale). NOAA has a G1 storm watch out for this date, though the timing of the strongest activity can shift.

Activity can change at short notice. Check again on the night.

Stargazing

Mixed sky conditions during the best available spell: 7 Nov, 19:00 GMT to 20:00 GMT.

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

Moon-free dark sky: 7 Nov, 18:35 GMT to 8 Nov, 05:25 GMT.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
7 Nov, 18:35 GMT to 19:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
7 Nov, 19:00 GMT to 20:00 GMT	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
7 Nov, 20:00 GMT to 21:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
7 Nov, 21:00 GMT to 22:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
7 Nov, 22:00 GMT to 23:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
7 Nov, 23:00 GMT to 8 Nov, 00:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
8 Nov, 00:00 GMT to 01:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
8 Nov, 01:00 GMT to 02:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
8 Nov, 02:00 GMT to 03:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
8 Nov, 03:00 GMT to 04:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
8 Nov, 04:00 GMT to 05:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
8 Nov, 05:00 GMT to 05:25 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.

Moon, darkness and meteor showers

Near-new moon, about 2% illuminated.

Moonrise around 8 Nov, 07:00 GMT.

Full darkness: 7 Nov, 18:35 GMT to 8 Nov, 05:25 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.

Leonids 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 473 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 Y Llethr on Saturday 7 November 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 8 November 2026Confidence: Medium

Overall hill weather76Good

Summit wind · 08:00-17:000-10 mph southwesterly Summit gusts · 08:00-17:005-15 mph Feels like-2 to 2°C PrecipitationLittle or none Cloud-free summit estimate50% Cloud base through day500-800 m Freezing levelAbove summit DaylightSunrise 07:25 · Sunset 16:33 · 9.1 hours daylight

The day on the hill

A good day on Y Llethr: dry, with light winds.

Wind

On the summit expect light winds of up to 10 mph, mainly south-westerly, with gusts of 5–15 mph at the windiest. Lower down on the open hillside the wind will be light, under 5 mph.

Cloud and visibility

Cloud on the tops early should lift off them by early afternoon. The cloud base could be as low as 500–800 m in the early afternoon. Mist or fog is possible in the valleys early on, clearing by about 10am.

Rain and ground

It should stay dry.

Warmth and kit

On the tops it will be around 2 to 6°C, feeling like -2 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 4:35pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

Cloud heights are particularly hard to pin down today. 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 1.9 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: 0 h
Midday: 1.2 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 0-10 mph. Gusts around 5-15 mph are possible on exposed ground.

66

Afternoon · 12:00–17:00 Excellent Summit winds around 0-10 mph. Gusts around 0-10 mph are possible on exposed ground. Summit cloud is more persistent early in this period, with better prospects later.

86

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 cold: dry, with light winds. 59Mixed · 600 m View detailsHide details

Night beginning Sunday 8 November 2026

Full overnight outlook

A mixed night to camp, mainly because of the cold. Light winds on open ground, gusting no more than about 20 mph. It should stay dry. A cold night, down to about 1°C around 600 m. A warm 3-season or 3–4 season bag rated to about -2°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain0.0 mm Open ground · 600 m8 mph · gusts 22 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about -2°C or lower

Elevation reference (open ground)

300 m59 · mixed

Wind / gust: 7 mph / 19 mph
Typical / low: 4.1°C / 1.3°C · much of the night
In cloud: 0% of modelled night
Condensation: Moderate

600 m59 · mixed

Wind / gust: 8 mph / 22 mph
Typical / low: 4.3°C / 0.8°C · much of the night
In cloud: 7% 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 -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 & scramblingBetaFair conditions for exposed scrambling. Good71 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Fair conditions for exposed scrambling. The rock should be mostly dry, though drainage lines and shaded holds may still be damp. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly mudstone or slate, 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. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceProbably dryPeak gust5-15 mphRain0.0 mm

Main concernmuch of the route may be in cloud

Representative rock around the summit Mudstone Hafotty Formation

Origin: Sedimentary
Broad rock-response group: Slate or mudstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Slate or mudstone in 71% of 17 BGS samples within 350 m
Rock-response profile: Moderate confidence

View the summit BGS record

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. 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.

Geological detail and BGS records

Mapped variation

3 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 Mudstone Hafotty Formation

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 Sandstone Hafotty Formation

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

Summit-area sample Sandstone and mudstone Rhinog Formation

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

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. Hazy, which dims the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-11-08. All times are UK local time.

Stargazing

Poor sky conditions during the best available spell: 8 Nov, 19:00 GMT to 20:00 GMT.

Mostly clear. Hazy, which dims the fainter stars.

Moon-free dark sky: 8 Nov, 18:30 GMT to 9 Nov, 05:30 GMT.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
8 Nov, 18:30 GMT to 19:00 GMT	Poor sky conditions Mostly clear. Hazy, which dims the fainter stars.
8 Nov, 19:00 GMT to 20:00 GMT	Poor sky conditions Mostly clear. Hazy, which dims the fainter stars.
8 Nov, 20:00 GMT to 21:00 GMT	Poor sky conditions Mostly clear. Hazy, which dims the fainter stars.
8 Nov, 21:00 GMT to 22:00 GMT	Poor sky conditions Mostly clear. Hazy, which dims the fainter stars.
8 Nov, 22:00 GMT to 23:00 GMT	Poor sky conditions Mostly clear. Hazy, which dims the fainter stars.
8 Nov, 23:00 GMT to 9 Nov, 00:00 GMT	Poor sky conditions Mostly clear. Hazy, which dims the fainter stars.
9 Nov, 00:00 GMT to 01:00 GMT	Poor sky conditions Mostly clear. Hazy, which dims the fainter stars.
9 Nov, 01:00 GMT to 02:00 GMT	Poor sky conditions Some breaks in the cloud, so stars at times. Hazy, which dims the fainter stars.
9 Nov, 02:00 GMT to 03:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
9 Nov, 03:00 GMT to 04:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
9 Nov, 04:00 GMT to 05:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
9 Nov, 05:00 GMT to 05:30 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.

Moon, darkness and meteor showers

Near-new moon, about 0% illuminated.

Full darkness: 8 Nov, 18:30 GMT to 9 Nov, 05:30 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.

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

Leonids 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 473 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 Y Llethr on Sunday 8 November 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

Monday 9 November 2026Confidence: Medium

Overall hill weather60Mixed

Summit wind · 08:00-17:0020-35 mph southeasterly Summit gusts · 08:00-17:0030-40 mph Feels like-4 to 0°C PrecipitationLittle or none Cloud-free summit estimate85% Cloud base through day500-1,300 m Freezing level600-900 m DaylightSunrise 07:27 · Sunset 16:31 · 9.1 hours daylight

The day on the hill

A mixed day on Y Llethr, with a blustery wind.

Wind

On the summit expect a south-easterly wind of 20–35 mph for most of the day, with gusts of 30–40 mph at the windiest. Lower down on the open hillside the wind will be light, under 10 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 60–70 mph.

Cloud and visibility

The tops should stay mostly clear of cloud. The cloud base could be as low as 500–800 m mid-morning. Mist or fog is possible in the valleys early on, clearing by about 4am. Good spells of sunshine are likely.

Rain and ground

It should stay dry.

Warmth and kit

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

Daylight

Sunset is around 4:30pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

Cloud height is hard to pin down, so the summit could be in or out of cloud at short notice. 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 7.7 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: 1.7 h
Midday: 4 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 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Gusts this strong can make walking into it hard work, with buffeting on ridges and edges.

62

Afternoon · 12:00–17:00 Mixed Summit winds around 25-35 mph. Gusts around 30-40 mph are possible on exposed ground. Gusts this strong can make walking into it hard work, with buffeting on ridges and edges.

59

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 600 m (gusts of about 40 mph). Lower down, a poor night to camp on open ground. 19Poor · 600 m View detailsHide details

Night beginning Monday 9 November 2026

Full overnight outlook

Too windy for an exposed pitch up around 600 m. Lower down, a poor night to camp on open ground. Gusts reach about 40 mph on open ground, 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. Dry to pitch, then some light rain overnight and into the morning, so expect to pack a wet tent. Up around 600 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 3°C around 300 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 rain1.6 mm Open ground · 600 m27 mph · gusts 40 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 0°C or lower

Elevation reference (open ground)

300 m39 · poor

Wind / gust: 23 mph / 33 mph
Typical / low: 3.7°C / 3.0°C · much of the night
In cloud: 0% of modelled night
Condensation: Moderate

600 m19 · very poor

Wind / gust: 27 mph / 40 mph
Typical / low: 3.7°C / 3.1°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 & scramblingBetaFair conditions for exposed scrambling: gusts of 30–40 mph. Mixed65 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Fair conditions for exposed scrambling. It should stay mostly dry, but a passing shower could leave the rock damp and slippery. Gusts of 30–40 mph could throw you off balance on exposed moves and ridges. The rock around the summit is mostly mudstone or slate, 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. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceDry initially; rain possiblePeak gust30-40 mphRainPossible · 25%

Main factorsgusts of 30–40 mphrain possible despite mostly dry conditions being favoured

Representative rock around the summit Mudstone Hafotty Formation

Origin: Sedimentary
Broad rock-response group: Slate or mudstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Slate or mudstone in 71% of 17 BGS samples within 350 m
Rock-response profile: Moderate confidence

View the summit BGS record

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. 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.

Geological detail and BGS records

Mapped variation

3 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 Mudstone Hafotty Formation

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 Sandstone Hafotty Formation

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

Summit-area sample Sandstone and mudstone Rhinog Formation

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

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 2026-11-09. All times are UK local time.

Aurora outlook

Nothing notable expected.

A broad activity outlook, not a forecast of a visible display. Cloud and activity can change before the night.

Stargazing

Poor sky conditions during the best available spell: 9 Nov, 22:00 GMT to 23:00 GMT.

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

Moon-free dark sky: 9 Nov, 18:30 GMT to 10 Nov, 05:30 GMT.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
9 Nov, 18:30 GMT to 19:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
9 Nov, 19:00 GMT to 20:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
9 Nov, 20:00 GMT to 21:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
9 Nov, 21:00 GMT to 22:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
9 Nov, 22:00 GMT to 23:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
9 Nov, 23:00 GMT to 10 Nov, 00:00 GMT	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
10 Nov, 00:00 GMT to 01:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
10 Nov, 01:00 GMT to 02:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
10 Nov, 02:00 GMT to 03:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
10 Nov, 03:00 GMT to 04:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times.
10 Nov, 04:00 GMT to 05:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times.
10 Nov, 05:00 GMT to 05:30 GMT	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

Near-new moon, about 1% illuminated.

Full darkness: 9 Nov, 18:30 GMT to 10 Nov, 05:30 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.

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

Leonids 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 473 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 Y Llethr on Monday 9 November 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 10 November 2026Confidence: Low

Overall hill weather44Poor

Summit wind · 08:00-17:0020-35 mph southeasterly Summit gusts · 08:00-17:0040-50 mph Feels like-6 to -2°C PrecipitationUp to around 2 mm Cloud-free summit estimate50% Cloud base through day600-2,700 m Freezing levelAbove summit DaylightSunrise 07:29 · Sunset 16:29 · 9.0 hours daylight

The day on the hill

A poor day on the tops of Y Llethr, with strong, gusty winds.

Wind

On the summit expect a south-easterly wind of around 30–40 mph first thing, easing to 15–25 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. If the windier forecast models are right, summit gusts could reach 70–80 mph.

Cloud and visibility

The tops are likely to drift in and out of cloud, with the best chance of a clear summit early in the morning. A few forecast models bring the cloud base down to around 400–700 m at times. The cloud base sits close to summit height, so the top could go in and out of cloud at short notice.

Rain and ground

Drizzle for much of the day. Some forecast models keep it drier in the morning.

Warmth and kit

On the tops it will be around 2 to 6°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. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 4:30pm, 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 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 5.2 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: 1.7 h
Midday: 2.4 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. 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. Rain is forecast during this period. Rain is possible during the morning, but forecast models disagree on whether it will fall.

46

Afternoon · 12:00–17:00 Poor Winds ease compared with the morning. Summit winds around 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period. Rain is possible during the afternoon, but forecast models disagree on whether it will fall.

43

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 4 mm of rain. 54Mixed · 600 m View detailsHide details

Night beginning Tuesday 10 November 2026

Full overnight outlook

A mixed night to camp, mainly because of the rain. Gusts reach about 25 mph on open ground, so peg out well and use the guylines. Look for shelter from the south. Expect about 4 mm of rain, with rain while you pitch and still falling when you pack up. Up around 600 m you'd likely be in cloud for part of the night: damp, and hard to find your way if you need to move. Overnight lows of about 8°C at 300 m. A 3-season bag rated to about 6°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain4.1 mm Open ground · 600 m17 mph · gusts 25 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 6°C or lower

Elevation reference (open ground)

300 m64 · reasonable

Wind / gust: 14 mph / 21 mph
Typical / low: 9.9°C / 8.0°C · several hours
In cloud: 0% of modelled night
Condensation: High

600 m54 · mixed

Wind / gust: 17 mph / 25 mph
Typical / low: 9.6°C / 8.2°C · much of the night
In cloud: 80% 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 6°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 is likely to be wet and slippery through the day. 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 mudstone or slate, 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. 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 gust40-50 mphRain2.7 mm

Main factorsgusts of 40–50 mphwet rock likelymuch of the route may be in cloud

Representative rock around the summit Mudstone Hafotty Formation

Origin: Sedimentary
Broad rock-response group: Slate or mudstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Slate or mudstone in 71% of 17 BGS samples within 350 m
Rock-response profile: Moderate confidence

View the summit BGS record

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. 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.

Geological detail and BGS records

Mapped variation

3 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 Mudstone Hafotty Formation

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 Sandstone Hafotty Formation

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

Summit-area sample Sandstone and mudstone Rhinog Formation

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

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. Rain at times. Hazy, which dims the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-11-10. All times are UK local time.

Aurora outlook

Nothing notable expected.

A broad activity outlook, not a forecast of a visible display. Cloud and activity can change before the night.

Stargazing

Poor sky conditions during the best available spell: 10 Nov, 19:00 GMT to 20:00 GMT.

Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.

Moon-free dark sky: 10 Nov, 18:30 GMT to 11 Nov, 05:30 GMT.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
10 Nov, 18:30 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.
10 Nov, 19:00 GMT to 20:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.
10 Nov, 20:00 GMT to 21:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.
10 Nov, 21:00 GMT to 22:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
10 Nov, 22:00 GMT to 23:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
10 Nov, 23:00 GMT to 11 Nov, 00:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
11 Nov, 00:00 GMT to 01:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
11 Nov, 01:00 GMT to 02:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
11 Nov, 02:00 GMT to 03:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
11 Nov, 03:00 GMT to 04:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
11 Nov, 04:00 GMT to 05:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.
11 Nov, 05:00 GMT to 05:30 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Hazy, which dims the fainter stars.

Moon, darkness and meteor showers

Near-new moon, about 3% illuminated.

Full darkness: 10 Nov, 18:30 GMT to 11 Nov, 05:30 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.

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

Leonids 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 473 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 Y Llethr on Tuesday 10 November 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 11 November 2026Confidence: Unavailable

Overall hill weather54Mixed

Summit wind · 08:00-17:005-20 mph southerly Summit gusts · 08:00-17:0015-25 mph Feels like2 to 6°C PrecipitationAround 5-10 mm Cloud-free summit estimate25% Cloud base through day400-700 m Freezing levelAbove summit DaylightSunrise 07:30 · Sunset 16:28 · 8.9 hours daylight

The day on the hill

A mixed day on Y Llethr, with rain for much of the day and cloud coming and going on the summit.

Wind

On the summit expect a southerly wind of 5–20 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

Expect the summit to be in cloud for most of the day. The cloud base could be as low as 400–700 m mid-afternoon. In cloud you'll be finding your way without landmarks, so carry navigation you trust and know how to use, with a backup such as a spare battery or a map and compass.

Rain and ground

Rain for much of the day, becoming heavier later. Expect 5–10 mm in total. Some forecast models keep it drier in the afternoon.

Warmth and kit

On the tops it will be around 6 to 10°C, feeling like 2 to 6°C in the wind. The freezing level is above the summits. A windproof and an extra layer for stops will help. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

A short day, with only about 9 hours of daylight. Sunset is around 4:30pm, 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 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.

57

Afternoon · 12:00–17:00 Mixed More rain is expected. Summit winds around 5-15 mph. Gusts around 10-20 mph are possible on exposed ground. Rain is forecast during this period. Some forecast models bring rain during the afternoon, while others keep it mostly dry.

52

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 Wednesday 11 November 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. Expect about 8 mm of rain, mostly early on, so you'll likely pitch in the rain. Up around 600 m you'd likely be in cloud for part of the night: damp, and hard to find your way if you need to move. Overnight lows of about 7°C at 300 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 m7 mph · gusts 22 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Elevation reference (open ground)

300 m59 · mixed

Wind / gust: 6 mph / 19 mph
Typical / low: 8.4°C / 6.9°C · much of the night
In cloud: 0% of modelled night
Condensation: High

600 m59 · mixed

Wind / gust: 7 mph / 22 mph
Typical / low: 8.4°C / 6.9°C · much of the night
In cloud: 47% 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 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. Poor29 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. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly mudstone or slate, 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. 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 mphRain12.4 mm

Main factorswet rock likelymuch of the route may be in cloud

Representative rock around the summit Mudstone Hafotty Formation

Origin: Sedimentary
Broad rock-response group: Slate or mudstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Slate or mudstone in 71% of 17 BGS samples within 350 m
Rock-response profile: Moderate confidence

View the summit BGS record

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. 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.

Geological detail and BGS records

Mapped variation

3 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 Mudstone Hafotty Formation

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 Sandstone Hafotty Formation

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

Summit-area sample Sandstone and mudstone Rhinog Formation

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

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. Rain at times. Hazy, which dims the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-11-11. All times are UK local time.

Aurora outlook

Nothing notable expected.

A broad activity outlook, not a forecast of a visible display. Cloud and activity can change before the night.

Stargazing

Poor sky conditions during the best available spell: 11 Nov, 19:00 GMT to 20:00 GMT.

Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.

Moon-free dark sky: 11 Nov, 18:25 GMT to 12 Nov, 05:35 GMT.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
11 Nov, 18:25 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.
11 Nov, 19:00 GMT to 20:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.
11 Nov, 20:00 GMT to 21:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.
11 Nov, 21:00 GMT to 22:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.
11 Nov, 22:00 GMT to 23:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times.
11 Nov, 23:00 GMT to 12 Nov, 00:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times.
12 Nov, 00:00 GMT to 01:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Limited model coverage.
12 Nov, 01:00 GMT to 02:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Limited model coverage.
12 Nov, 02:00 GMT to 03:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Limited model coverage.
12 Nov, 03:00 GMT to 04:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Limited model coverage.
12 Nov, 04:00 GMT to 05:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Limited model coverage.
12 Nov, 05:00 GMT to 05:35 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Limited model coverage.

Moon, darkness and meteor showers

Crescent moon, about 7% illuminated.

Full darkness: 11 Nov, 18:25 GMT to 12 Nov, 05:35 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.

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

Leonids 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 473 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 Y Llethr on Wednesday 11 November 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 12 November 2026Confidence: Unavailable

Overall hill weather88Excellent

Summit wind · 08:00-17:000-15 mph northeasterly Summit gusts · 08:00-17:0010-20 mph Feels like-4 to 0°C PrecipitationUp to around 2 mm Cloud-free summit estimate50% Cloud base through day800-1,400 m Freezing levelAbove summit DaylightSunrise 07:32 · Sunset 16:26 · 8.9 hours daylight

The day on the hill

A fine day on Y Llethr: light winds.

Wind

On the summit expect light winds of up to 15 mph, mainly north-easterly, with gusts of 10–20 mph at the windiest.

Cloud and visibility

The tops are likely to drift in and out of cloud, with the best chance of a clear summit mid-morning. A few forecast models bring the cloud base down to around 600–900 m at times. The cloud base sits close to summit height, so the top could go in and out of cloud at short notice.

Rain and ground

Drizzle sets in during the early afternoon. It will be wet underfoot after recent rain.

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.

Daylight

A short day, with only about 9 hours of daylight. Sunset is around 4:25pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

It's still seven 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 Good Summit winds around 0-10 mph. Gusts around 5-15 mph are possible on exposed ground. Summit cloud is more persistent early in this period, with better prospects later.

83

Afternoon · 12:00–17:00 Excellent Summit winds around 5-15 mph. Gusts around 10-20 mph are possible on exposed ground. Rain is forecast during this period.

92

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

Overnight · 17:00–08:00Wild campingBetaA poor night to camp on open ground: a frost, down to 0°C. 39Poor · 600 m View detailsHide details

Night beginning Thursday 12 November 2026

Full overnight outlook

A poor night to camp on open ground. Gusts reach about 30 mph on open ground, so peg out well and use the guylines. Look for shelter from the northeast. It should stay dry. A frost at every height we checked (300-600 m), down to about 0°C. A warm 3-season or 3–4 season bag rated to about -4°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain0.1 mm Open ground · 600 m16 mph · gusts 29 mph Morning pack-upNo wet signal Sleeping-bag warmthISO comfort rating about -4°C or lower

Moon overnight

Waxing crescent moon

Illuminated disc: 13%
Moonrise: Outside this window
Moonset: 17:47 GMT

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

Overnight window: 12 Nov, 17:00 GMT to 13 Nov, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m39 · poor

Wind / gust: 14 mph / 24 mph
Typical / low: -0.1°C / -0.4°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m39 · poor

Wind / gust: 16 mph / 29 mph
Typical / low: -0.1°C / -0.4°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

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 -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 & scramblingBetaMixed conditions for exposed scrambling: wet, slippery rock. Mixed55 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Mixed conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. The rock around the summit is mostly mudstone or slate, 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. 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 gust10-20 mphRain0.6 mm

Main concernwet rock likely

Representative rock around the summit Mudstone Hafotty Formation

Origin: Sedimentary
Broad rock-response group: Slate or mudstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Slate or mudstone in 71% of 17 BGS samples within 350 m
Rock-response profile: Moderate confidence

View the summit BGS record

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. 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.

Geological detail and BGS records

Mapped variation

3 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 Mudstone Hafotty Formation

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 Sandstone Hafotty Formation

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

Summit-area sample Sandstone and mudstone Rhinog Formation

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

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 darkBetaNight-sky guidance is unavailable for this night. View forecastClose forecast

After dark: aurora and stargazing

Night-sky guidance is unavailable for this night. This does not mean clear skies or no aurora.

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 Y Llethr on Thursday 12 November 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

Y Llethr 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

3 rock types appear in the mapped samples

After dark: aurora and stargazing

Aurora is unlikely on this night

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

3 rock types appear in the mapped samples

After dark: aurora and stargazing

A noticeable aurora display is unlikely; any glow may be faint or camera-only

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

3 rock types appear in the mapped samples

After dark: aurora and stargazing

Aurora is unlikely on this night

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

Elevation reference (open ground)

Full climbing & scrambling outlook

3 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

Elevation reference (open ground)

Full climbing & scrambling outlook

3 rock types appear in the mapped samples

After dark: aurora and stargazing

Aurora outlook

Stargazing

Darkness of the surroundings

The day on the hill