A poor day on the tops of Garnedd Uchaf, with strong, gusty winds and sleet or snow up high.
Wind
On the summit expect a westerly wind of around 10–20 mph first thing, rising to 30–40 mph by mid-afternoon, with gusts of 40–50 mph at the windiest. Lower down on the open hillside it will be more like 15–25 mph. Gusts like that are strong enough to knock you off balance, so take care near edges and on narrow ridges.
Cloud and visibility
The tops are likely to drift in and out of cloud, with the best chance of a clear summit mid-afternoon. The cloud base could be as low as 300–600 m early in the morning. 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
Sleet is possible on the tops, and it could turn to snow if it is a little colder. Heavy rain at first, clearing by mid-afternoon. Expect 10–20 mm in total, measured as melted water, so any snow would lie deeper. Totals are uncertain and could be higher.
Warmth and kit
On the tops it will be around 0 to 4°C, feeling like -8 to -4°C in the wind. It will feel colder later as the wind picks up. The freezing level falls through the day, to around 1000–1300 m by midday. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 6:05pm, so allow time to get off the hill before dark, and carry a head torch.
Forecast confidence
There is some disagreement between forecast models on wind strength. 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 1.3 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.
Cloud may obscure this summit even while the surrounding model grid indicates sunshine. The low cloud-free summit estimate is a reason to be cautious about expecting views.
Morning · 08:00–12:00
PoorSummit winds around 5-15 mph early in the morning, strengthening to 20-30 mph later. Gusts around 30-40 mph are possible on exposed ground. Rain is forecast during this period. Rain is forecast during the morning, but models differ considerably on the amount.
12
Afternoon · 12:00–17:00
Severe hill conditionsWinds strengthen compared with the morning. Summit winds around 25-40 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. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period. Rain is forecast during the afternoon, but models differ considerably on the amount.
-8
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 above about 600 m (gusts of about 50 mph and about 3 mm of rain). Lower down, a poor night to camp on open ground.19Poor · 600 mView detailsHide details
Night beginning Wednesday 21 October 2026
Full overnight outlook
Too windy for an exposed pitch above about 600 m. Lower down, a poor night to camp on open ground. Gusts reach about 50 mph around 900 m and nearer 35 mph around 300 m, enough to damage a tent on open ground. Pitch low down and in real shelter, or leave it for another night. Dry to pitch, then about 3 mm of rain overnight and into the morning, so expect to pack a wet tent. Above about 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 2°C around 900 m. A warm 3-season or 3–4 season bag rated to about 0°C comfort, and a warm mat, should do. Allow more if you sleep cold.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 21 Oct, 17:00 BST to 22 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m39 · poor
Wind / gust
16 mph / 37 mph
Typical / low
5.2°C / 4.5°C · several hours
In cloud
0% of modelled night
Condensation
Moderate
600 m19 · very poor
Wind / gust
19 mph / 44 mph
Typical / low
4.2°C / 3.7°C · much of the night
In cloud
33% of modelled night
Condensation
High
900 m9 · very poor
Wind / gust
23 mph / 52 mph
Typical / low
2.1°C / 1.7°C · much of the night
In cloud
40% of modelled night
Condensation
High
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.
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Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 40–50 mph.Poor0View 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 volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross basalt, which grips well when dry and can be very slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust40-50 mphRain11.0 mm
Main factorsgusts of 40–50 mphwet rock likelymuch of the route may be in cloud
Representative rock around the summit and along available routes
Volcaniclastic rockFoel Fras Volcanic Complex
Origin
Sedimentary and igneous
Broad rock-response group
Volcanic rock
Mapping
BGS Geology 50K · 1:50,000
Summit area
Volcanic rock in 88% of 17 BGS samples within 350 m
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Carneddau Aber Falls
volcanic rock, granite, gneiss or gabbro
Geological detail and BGS records
Mapped variation
5 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
Volcaniclastic rockFoel Fras Volcanic Complex576–813 m samplesSeen on Peak Carneddau Aber Falls
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
BasaltFoel Grach Basalt Formation932–1,053 m samplesSeen on Peak Carneddau Aber Falls
Basalt is a dark volcanic rock. It grips well when dry and can be very slippery when wet. It is often blocky and shattered, with loose rubble on ledges.
BGS record →
Route sample
MicrogranodioriteUnnamed Igneous Intrusion, OrdovicianAround 342 mSeen on Peak Carneddau Aber Falls
Granite is a coarse, crystalline rock. It has excellent friction when dry and clean and is fair when wet, but greasy where there is lichen or moss. It is generally solid, but weathers into rounded slabs and blocks, and loose granite grit on slabs can roll underfoot like ball bearings.
BGS record →
Route sample
TrachyandesiteUnnamed Igneous Intrusion, OrdovicianAround 450 mSeen on Peak Carneddau Aber Falls
Andesite is a hard volcanic rock. It grips well when dry and is fair when wet, though polished holds on popular routes get slippery. It is generally solid, but shattered in gullies and on broken ground.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup
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.
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 darkBetaNo sky forecast for this night yet. Moon and darkness times are shown separately.View forecastClose forecast
After dark: aurora and stargazing
Night beginning 2026-10-21. 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 3.7 (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
No sky forecast for this night yet. Moon and darkness times are shown separately.
Moon-free dark sky: 22 Oct, 03:00 BST to 06:00 BST.
Moon, darkness and meteor showers
Gibbous moon, about 80% illuminated.
Moonset around 22 Oct, 03:00 BST.
Full darkness: 21 Oct, 20:05 BST to 22 Oct, 06:00 BST.
Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.
Southern Taurids are active on this night. Activity may be much lower away from the peak.
Orionids are active on this night. Activity may be much lower away from the peak.
Northern Taurids are active on this night. Activity may be much lower away from the peak.
Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.
Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.
Darkness of the surroundings
Estimated darkness rank 906 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.
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 Garnedd Uchaf on Wednesday 21 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
Summit wind · 08:00-17:0010-20 mph southwesterlySummit gusts · 08:00-17:0020-30 mphFeels like-6 to -2°CPrecipitationUp to around 2 mmCloud-free summit estimate70%Cloud base through day400-1,600 mFreezing level1,000-1,300 mDaylightSunrise 07:54 · Sunset 18:05 · 10.2 hours daylight
The day on the hill
A good day on Garnedd Uchaf: light winds.
Wind
On the summit expect a south-westerly wind of 10–20 mph for most of the day, with gusts of 20–30 mph at the windiest.
Cloud and visibility
Cloud on the tops early should lift off them by mid-morning. The cloud base could be as low as 400–700 m early in the morning. It will look largely cloudy overhead, but that cloud should mostly stay above the tops. The air should be clear, so expect far-reaching views as long as the tops stay clear.
Rain and ground
A band of rain crosses mid-morning, clearing by midday. More rain follows after dark. Some forecast models keep it drier later on. It will be wet underfoot after recent rain.
Warmth and kit
On the tops it will be around 0 to 4°C, feeling like -6 to -2°C in the wind. The freezing level is close to summit height. Take a hat, gloves, a windproof and a spare warm layer.
Daylight
Sunset is around 6:05pm, so allow time to get off the hill before dark, and carry a head torch.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 5.7 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.
Morning · 08:00–12:00
MixedSummit winds around 10-20 mph. Gusts around 20-30 mph are possible on exposed ground. Rain is forecast during this period.
62
Afternoon · 12:00–17:00
ExcellentSummit winds around 10-20 mph. Gusts around 15-25 mph are possible on exposed ground.
87
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 above about 600 m (gusts of about 55 mph and around 19 mm of rain). Lower down, a poor night to camp on open ground.9Poor · 600 mView detailsHide details
Night beginning Thursday 22 October 2026
Full overnight outlook
Too windy for an exposed pitch above about 600 m. Lower down, a poor night to camp on open ground. Gusts reach about 55 mph around 900 m and nearer 40 mph around 300 m, strong enough to flatten or tear a tent. Pitch low down and in real shelter, or leave it for another night. The wind swings from southerly to southwesterly overnight, so a pitch sheltered at dusk may not be by morning. Expect a wet night, around 19 mm of rain, with rain while you pitch and still falling when you pack up. Above about 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 4°C at 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.
Cloud at the reference camping height may hide the Moon. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 22 Oct, 17:00 BST to 23 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m39 · poor
Wind / gust
19 mph / 39 mph
Typical / low
7.4°C / 6.6°C · much of the night
In cloud
0% of modelled night
Condensation
High
600 m9 · very poor
Wind / gust
23 mph / 47 mph
Typical / low
6.3°C / 5.6°C · much of the night
In cloud
47% of modelled night
Condensation
High
900 m9 · very poor
Wind / gust
27 mph / 55 mph
Typical / low
4.4°C / 3.5°C · much of the night
In cloud
53% 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.
Poor conditions for exposed scrambling. After recent rain the rock may still be wet in places, especially shaded holds and drainage lines. Gusts of 20–30 mph will be noticeable on exposed ridges. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross basalt, which grips well when dry and can be very slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceDry overhead; seepage uncertainPeak gust20-30 mphRain0.5 mm
Main concerndamp or incompletely dried rock possible
Representative rock around the summit and along available routes
Volcaniclastic rockFoel Fras Volcanic Complex
Origin
Sedimentary and igneous
Broad rock-response group
Volcanic rock
Mapping
BGS Geology 50K · 1:50,000
Summit area
Volcanic rock in 88% of 17 BGS samples within 350 m
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Carneddau Aber Falls
volcanic rock, granite, gneiss or gabbro
Geological detail and BGS records
Mapped variation
5 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
Volcaniclastic rockFoel Fras Volcanic Complex576–813 m samplesSeen on Peak Carneddau Aber Falls
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
BasaltFoel Grach Basalt Formation932–1,053 m samplesSeen on Peak Carneddau Aber Falls
Basalt is a dark volcanic rock. It grips well when dry and can be very slippery when wet. It is often blocky and shattered, with loose rubble on ledges.
BGS record →
Route sample
MicrogranodioriteUnnamed Igneous Intrusion, OrdovicianAround 342 mSeen on Peak Carneddau Aber Falls
Granite is a coarse, crystalline rock. It has excellent friction when dry and clean and is fair when wet, but greasy where there is lichen or moss. It is generally solid, but weathers into rounded slabs and blocks, and loose granite grit on slabs can roll underfoot like ball bearings.
BGS record →
Route sample
TrachyandesiteUnnamed Igneous Intrusion, OrdovicianAround 450 mSeen on Peak Carneddau Aber Falls
Andesite is a hard volcanic rock. It grips well when dry and is fair when wet, though polished holds on popular routes get slippery. It is generally solid, but shattered in gullies and on broken ground.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup
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.
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 darkBetaNo sky forecast for this night yet. Moon and darkness times are shown separately.View forecastClose forecast
After dark: aurora and stargazing
Night beginning 2026-10-22. All times are UK local time.
Aurora is unlikely on this night
Too quiet for a likely sighting from here. Activity peaks around Kp 2.7 (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.
Activity can change at short notice. Check again on the night.
Stargazing
No sky forecast for this night yet. Moon and darkness times are shown separately.
Moon-free dark sky: 23 Oct, 04:15 BST to 06:00 BST.
Moon, darkness and meteor showers
Gibbous moon, about 88% illuminated.
Moonset around 23 Oct, 04:15 BST.
Full darkness: 22 Oct, 20:00 BST to 23 Oct, 06:00 BST.
Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.
Southern Taurids are active on this night. Activity may be much lower away from the peak.
Orionids are active on this night. Activity may be much lower away from the peak.
Northern Taurids are active on this night. Activity may be much lower away from the peak.
Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.
Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.
Darkness of the surroundings
Estimated darkness rank 906 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.
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 Garnedd Uchaf on Thursday 22 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
A wild day on the tops of Garnedd Uchaf, with a real risk of thunderstorms and very strong, gusty winds. Not a day for the summit.
Things to watch
There is a real risk of thunderstorms from the morning into the afternoon. Keep off exposed summits and ridges while storms are around. Storms can bring sudden strong gusts and heavy rain. Storm timing could easily shift by a few hours. Burns and rivers are likely to be in spate through much of the day and into the evening, so unbridged crossings could be difficult or impossible. Timings are rough. Turn back if a crossing looks unsafe.
Wind
On the summit expect a north-westerly wind of around 20–30 mph first thing, rising to 40–50 mph by midday, with gusts of 50–60 mph at the windiest. Lower down on the open hillside it will be more like 15–25 mph. Gusts like that are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. If the windier forecast models are right, summit gusts could reach 65–75 mph.
Cloud and visibility
Cloud on the tops early should lift off them by early afternoon. The cloud base could be as low as 400–700 m mid-morning. A few forecast models bring it lower still, to around 300–600 m. Visibility may drop briefly in showers.
Rain and ground
Heavy rain at first, clearing by mid-afternoon. Expect 10–20 mm in total. Totals are uncertain and could be higher. It will be wet underfoot after recent rain.
Warmth and kit
On the tops it will be around 0 to 4°C, feeling like -10 to -6°C in the wind. The freezing level is close to summit height. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 6:05pm, so allow time to get off the hill before dark, and carry a head torch.
Forecast confidence
It's still two days off and could change, so check again nearer the time.
Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans. Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 4.2 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.
Morning · 08:00–12:00
Severe hill conditionsSummit winds around 15-25 mph early in the morning, strengthening to 35-45 mph later. Gusts around 50-60 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period. Rain is forecast during the morning, but models differ considerably on the amount.
-46
Afternoon · 12:00–17:00
Severe hill conditionsWinds strengthen compared with the morning. Summit winds around 35-45 mph. Gusts around 50-60 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period. Some forecast models bring rain during the afternoon, while others keep it mostly dry.
-30
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 60 mph.9Poor · 600 mView detailsHide details
Night beginning Friday 23 October 2026
Full overnight outlook
Not a night to camp on the open hill. Gusts reach about 60 mph around 900 m and nearer 40 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. The wind swings from northwesterly to westerly overnight, so a pitch sheltered at dusk may not be by morning. Dry to pitch, then a little rain overnight and into the morning, so expect to pack a wet tent. A cold night, down to about 2°C around 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 23 Oct, 17:00 BST to 24 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m19 · very poor
Wind / gust
24 mph / 41 mph
Typical / low
5.5°C / 5.1°C · much of the night
In cloud
0% of modelled night
Condensation
Low
600 m9 · very poor
Wind / gust
29 mph / 50 mph
Typical / low
4.4°C / 4.2°C · much of the night
In cloud
0% of modelled night
Condensation
Low
900 m9 · very poor
Wind / gust
34 mph / 58 mph
Typical / low
1.8°C / 1.6°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.
Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 50–60 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Cloud on the tops may make route-finding and retreat harder. There is a real risk of thunderstorms from the morning into the afternoon. Keep off exposed rock and ridges while storms are around. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross basalt, which grips well when dry and can be very slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust50-60 mphRain15.7 mm
Main factorshigh thunderstorm risk on exposed groundgusts of 50–60 mphwet rock likely
Representative rock around the summit and along available routes
Volcaniclastic rockFoel Fras Volcanic Complex
Origin
Sedimentary and igneous
Broad rock-response group
Volcanic rock
Mapping
BGS Geology 50K · 1:50,000
Summit area
Volcanic rock in 88% of 17 BGS samples within 350 m
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Carneddau Aber Falls
volcanic rock, granite, gneiss or gabbro
Geological detail and BGS records
Mapped variation
5 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
Volcaniclastic rockFoel Fras Volcanic Complex576–813 m samplesSeen on Peak Carneddau Aber Falls
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
BasaltFoel Grach Basalt Formation932–1,053 m samplesSeen on Peak Carneddau Aber Falls
Basalt is a dark volcanic rock. It grips well when dry and can be very slippery when wet. It is often blocky and shattered, with loose rubble on ledges.
BGS record →
Route sample
MicrogranodioriteUnnamed Igneous Intrusion, OrdovicianAround 342 mSeen on Peak Carneddau Aber Falls
Granite is a coarse, crystalline rock. It has excellent friction when dry and clean and is fair when wet, but greasy where there is lichen or moss. It is generally solid, but weathers into rounded slabs and blocks, and loose granite grit on slabs can roll underfoot like ball bearings.
BGS record →
Route sample
TrachyandesiteUnnamed Igneous Intrusion, OrdovicianAround 450 mSeen on Peak Carneddau Aber Falls
Andesite is a hard volcanic rock. It grips well when dry and is fair when wet, though polished holds on popular routes get slippery. It is generally solid, but shattered in gullies and on broken ground.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup
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.
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 darkBetaNo sky forecast for this night yet. Moon and darkness times are shown separately.View forecastClose forecast
After dark: aurora and stargazing
Night beginning 2026-10-23. 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 3.3 (on a 0 to 9 scale).
Activity can change at short notice. Check again on the night.
Stargazing
No sky forecast for this night yet. Moon and darkness times are shown separately.
Moon-free dark sky: 24 Oct, 05:35 BST to 06:00 BST.
Moon, darkness and meteor showers
Gibbous moon, about 94% illuminated.
Moonset around 24 Oct, 05:35 BST.
Full darkness: 23 Oct, 20:00 BST to 24 Oct, 06:00 BST.
Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.
Southern Taurids are active on this night. Activity may be much lower away from the peak.
Orionids are active on this night. Activity may be much lower away from the peak.
Northern Taurids are active on this night. Activity may be much lower away from the peak.
Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.
Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.
Darkness of the surroundings
Estimated darkness rank 906 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.
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 Garnedd Uchaf on Friday 23 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
A poor day on the tops of Garnedd Uchaf, with very strong, gusty winds and rain for much of the day.
Things to watch
Burns could rise quickly through the day and overnight. Timings are rough. Turn back if a crossing looks unsafe.
Wind
On the summit expect a south-westerly wind of around 30–40 mph first thing, rising to 40–50 mph by early afternoon, with gusts of 55–65 mph at the windiest. Lower down on the open hillside it will be more like 15–25 mph. Gusts like that are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. If the windier forecast models are right, summit gusts could reach 70–80 mph.
Cloud and visibility
The tops should stay mostly clear of cloud. The cloud base could be as low as 600–900 m mid-morning. A few forecast models bring it lower still, to around 400–700 m. Visibility may drop briefly in showers. It will look largely cloudy overhead, but that cloud should mostly stay above the tops.
Rain and ground
Rain for much of the day, becoming heavier through the afternoon. Expect 10–20 mm in total. Totals are uncertain and could be higher. The ground is very wet after recent rain, so expect boggy paths.
Warmth and kit
On the tops it will be around 2 to 6°C, feeling like -6 to -2°C in the wind. It turns milder through the day. The freezing level is above the summits. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 6pm, so allow time to get off the hill before dark, and carry a head torch.
Forecast confidence
There is some disagreement between forecast models on wind strength. 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 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.
Morning · 08:00–12:00
PoorSummit winds around 25-35 mph early in the morning, strengthening to 35-45 mph later. Gusts around 50-60 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Summit cloud becomes more persistent later. Rain is forecast during this period. Some forecast models bring rain during the morning, while others keep it mostly dry.
14
Afternoon · 12:00–17:00
Severe hill conditionsMore rain is expected. Summit winds around 35-50 mph. Gusts around 55-65 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period. Rain is forecast during the afternoon, but models differ considerably on the amount.
-5
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 80 mph and about 7 mm of rain.0Poor · 600 mView detailsHide details
Night beginning Saturday 24 October 2026
Full overnight outlook
Not a night to camp on the open hill. Gusts reach about 80 mph around 900 m and nearer 55 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. Expect about 7 mm of rain, with rain while you pitch and still falling when you pack up. A cold night, down to about 2°C around 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold. The ground will be sodden after recent rain, so pick a firm, well-drained pitch.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 24 Oct, 17:00 BST to 25 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m9 · very poor
Wind / gust
38 mph / 56 mph
Typical / low
7.0°C / 6.4°C · much of the night
In cloud
0% of modelled night
Condensation
Low
600 m0 · very poor
Wind / gust
46 mph / 68 mph
Typical / low
4.8°C / 4.1°C · much of the night
In cloud
0% of modelled night
Condensation
Low
900 m0 · very poor
Wind / gust
54 mph / 80 mph
Typical / low
2.6°C / 2.1°C · much of the night
In cloud
0% of modelled night
Condensation
Low
Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.
The ground is likely to be very wet after recent rain. Expect boggy approaches and choose a durable pitch carefully.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 55–65 mph.Poor0View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 55–65 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross basalt, which grips well when dry and can be very slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust55-65 mphRain15.9 mm
Main factorsgusts of 55–65 mphwet rock likely
Representative rock around the summit and along available routes
Volcaniclastic rockFoel Fras Volcanic Complex
Origin
Sedimentary and igneous
Broad rock-response group
Volcanic rock
Mapping
BGS Geology 50K · 1:50,000
Summit area
Volcanic rock in 88% of 17 BGS samples within 350 m
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Carneddau Aber Falls
volcanic rock, granite, gneiss or gabbro
Geological detail and BGS records
Mapped variation
5 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
Volcaniclastic rockFoel Fras Volcanic Complex576–813 m samplesSeen on Peak Carneddau Aber Falls
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
BasaltFoel Grach Basalt Formation932–1,053 m samplesSeen on Peak Carneddau Aber Falls
Basalt is a dark volcanic rock. It grips well when dry and can be very slippery when wet. It is often blocky and shattered, with loose rubble on ledges.
BGS record →
Route sample
MicrogranodioriteUnnamed Igneous Intrusion, OrdovicianAround 342 mSeen on Peak Carneddau Aber Falls
Granite is a coarse, crystalline rock. It has excellent friction when dry and clean and is fair when wet, but greasy where there is lichen or moss. It is generally solid, but weathers into rounded slabs and blocks, and loose granite grit on slabs can roll underfoot like ball bearings.
BGS record →
Route sample
TrachyandesiteUnnamed Igneous Intrusion, OrdovicianAround 450 mSeen on Peak Carneddau Aber Falls
Andesite is a hard volcanic rock. It grips well when dry and is fair when wet, though polished holds on popular routes get slippery. It is generally solid, but shattered in gullies and on broken ground.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup
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.
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 darkBetaNo sky forecast for this night yet. Moon and darkness times are shown separately.View forecastClose forecast
After dark: aurora and stargazing
Night beginning 2026-10-24. All times are UK local time.
Stargazing
No sky forecast for this night yet. Moon and darkness times are shown separately.
A bright moon is up all through the dark hours, washing out fainter stars and meteors.
Moon, darkness and meteor showers
Near-full moon, about 98% illuminated.
Moonset around 25 Oct, 06:00 GMT.
Full darkness: 24 Oct, 19:55 BST to 25 Oct, 05:05 GMT.
Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.
Southern Taurids are active on this night. Activity may be much lower away from the peak.
Orionids are active on this night. Activity may be much lower away from the peak.
Northern Taurids are active on this night. Activity may be much lower away from the peak.
Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.
Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.
Darkness of the surroundings
Estimated darkness rank 906 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.
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 Garnedd Uchaf on Saturday 24 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
A poor day on the tops of Garnedd Uchaf, with very strong, gusty winds and drizzle for much of the day.
Wind
On the summit expect a north-westerly wind of 35–50 mph for most of the day, with gusts of 60–70 mph at the windiest. Lower down on the open hillside it will be more like 15–25 mph. Gusts like that are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges.
Cloud and visibility
The tops are likely to drift in and out of cloud, with the best chance of a clear summit around midday. The cloud base could be as low as 700–1000 m mid-morning. A few forecast models bring it lower still, to around 500–800 m. Visibility may drop briefly in showers.
Rain and ground
Drizzle for much of the day. Expect 2–5 mm in total. Some forecast models keep it drier in the morning. The ground is very wet after recent rain, so expect boggy paths.
Warmth and kit
On the tops it will be around 0 to 4°C, feeling like -8 to -4°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 5pm, so allow time to get off the hill before dark, and carry a head torch.
Forecast confidence
There is some disagreement between forecast models on wind strength. It's still four days off and could change, so check again nearer the time.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 7.8 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.
Morning · 08:00–12:00
Severe hill conditionsSummit winds around 40-50 mph. Gusts around 60-70 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Summit cloud becomes more persistent later. Rain is forecast during this period. Rain is possible during the morning, but forecast models disagree on whether it will fall.
-2
Afternoon · 12:00–17:00
PoorSummit winds around 35-45 mph. Gusts around 50-60 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period. Rain is possible during the afternoon, but forecast models disagree on whether it will fall.
27
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 above about 600 m (gusts of about 55 mph). Lower down, a poor night to camp on open ground.9Poor · 600 mView detailsHide details
Night beginning Sunday 25 October 2026
Full overnight outlook
Too windy for an exposed pitch above about 600 m. Lower down, a poor night to camp on open ground. Gusts reach about 55 mph around 900 m and nearer 40 mph around 300 m, strong enough to flatten or tear a tent. Pitch low down and in real shelter, or leave it for another night. The wind swings from northwesterly to southwesterly overnight, so a pitch sheltered at dusk may not be by morning. Dry to pitch, then some light rain by morning, so you'll likely pack up in the wet. A cold night, down to about 2°C around 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold. The ground will be sodden after recent rain, so pick a firm, well-drained pitch.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 25 Oct, 17:00 GMT to 26 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m39 · poor
Wind / gust
17 mph / 39 mph
Typical / low
5.8°C / 5.0°C · a brief spell
In cloud
0% of modelled night
Condensation
Low
600 m9 · very poor
Wind / gust
20 mph / 47 mph
Typical / low
4.9°C / 4.5°C · much of the night
In cloud
0% of modelled night
Condensation
Low
900 m9 · very poor
Wind / gust
23 mph / 56 mph
Typical / low
2.7°C / 2.2°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.
The ground is likely to be very wet after recent rain. Expect boggy approaches and choose a durable pitch carefully.
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 60–70 mph.Poor0View 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 60–70 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross basalt, which grips well when dry and can be very slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust60-70 mphRain3.0 mm
Main factorsgusts of 60–70 mphwet rock likely
Representative rock around the summit and along available routes
Volcaniclastic rockFoel Fras Volcanic Complex
Origin
Sedimentary and igneous
Broad rock-response group
Volcanic rock
Mapping
BGS Geology 50K · 1:50,000
Summit area
Volcanic rock in 88% of 17 BGS samples within 350 m
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Carneddau Aber Falls
volcanic rock, granite, gneiss or gabbro
Geological detail and BGS records
Mapped variation
5 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
Volcaniclastic rockFoel Fras Volcanic Complex576–813 m samplesSeen on Peak Carneddau Aber Falls
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
BasaltFoel Grach Basalt Formation932–1,053 m samplesSeen on Peak Carneddau Aber Falls
Basalt is a dark volcanic rock. It grips well when dry and can be very slippery when wet. It is often blocky and shattered, with loose rubble on ledges.
BGS record →
Route sample
MicrogranodioriteUnnamed Igneous Intrusion, OrdovicianAround 342 mSeen on Peak Carneddau Aber Falls
Granite is a coarse, crystalline rock. It has excellent friction when dry and clean and is fair when wet, but greasy where there is lichen or moss. It is generally solid, but weathers into rounded slabs and blocks, and loose granite grit on slabs can roll underfoot like ball bearings.
BGS record →
Route sample
TrachyandesiteUnnamed Igneous Intrusion, OrdovicianAround 450 mSeen on Peak Carneddau Aber Falls
Andesite is a hard volcanic rock. It grips well when dry and is fair when wet, though polished holds on popular routes get slippery. It is generally solid, but shattered in gullies and on broken ground.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup
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.
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 darkBetaNo sky forecast for this night yet. Moon and darkness times are shown separately.View forecastClose forecast
After dark: aurora and stargazing
Night beginning 2026-10-25. 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
No sky forecast for this night yet. Moon and darkness times are shown separately.
A bright moon is up all through the dark hours, washing out fainter stars and meteors.
Moon, darkness and meteor showers
Near-full moon, about 100% illuminated.
Moonset around 26 Oct, 07:25 GMT.
Full darkness: 25 Oct, 18:55 GMT to 26 Oct, 05:05 GMT.
Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.
Southern Taurids are active on this night. Activity may be much lower away from the peak.
Orionids are active on this night. Activity may be much lower away from the peak.
Northern Taurids are active on this night. Activity may be much lower away from the peak.
Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.
Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.
Darkness of the surroundings
Estimated darkness rank 906 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.
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 Garnedd Uchaf on Sunday 25 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
A poor day on the tops of Garnedd Uchaf, with strong, gusty winds and drizzle for much of the day.
Wind
On the summit expect a south-westerly wind of around 20–30 mph first thing, rising to 30–40 mph by mid-afternoon, with gusts of 45–55 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 55–65 mph. It gets windier still after dark, with summit gusts of 45–55 mph, so bear that in mind if you will be out late.
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. The cloud base could be as low as 400–700 m in the early afternoon.
Rain and ground
Drizzle for much of the day. Expect 2–5 mm in total. Totals are uncertain and could be higher. The ground is very wet after recent rain, so expect boggy paths.
Warmth and kit
On the tops it will be around 2 to 6°C, feeling like -4 to 0°C in the wind. It turns milder through the day. The freezing level is above the summits. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 4:55pm, 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 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.
Morning · 08:00–12:00
PoorSummit winds around 20-35 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. Rain is forecast during this period.
34
Afternoon · 12:00–17:00
PoorWinds strengthen compared with the morning. Summit winds around 30-40 mph. Gusts around 45-55 mph are possible on exposed ground. Gusts this strong can knock you off balance, so take care near edges and on narrow ridges. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period.
2
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 60 mph and heavy rain, around 20 mm.9Poor · 600 mView detailsHide details
Night beginning Monday 26 October 2026
Full overnight outlook
Not a night to camp on the open hill. Gusts reach about 60 mph around 900 m and nearer 45 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. Expect heavy rain, around 20 mm, with rain while you pitch and still falling when you pack up. Overnight lows of about 7°C at 900 m. A 3-season bag rated to about 6°C comfort, and a warm mat, should do. Allow more if you sleep cold. The ground will be sodden after recent rain, so pick a firm, well-drained pitch.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 26 Oct, 17:00 GMT to 27 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m19 · very poor
Wind / gust
28 mph / 44 mph
Typical / low
13.0°C / 10.3°C
In cloud
0% of modelled night
Condensation
Moderate
600 m9 · very poor
Wind / gust
34 mph / 53 mph
Typical / low
12.1°C / 8.8°C · a brief spell
In cloud
0% of modelled night
Condensation
High
900 m0 · very poor
Wind / gust
39 mph / 62 mph
Typical / low
10.9°C / 7.3°C · several hours
In cloud
0% of modelled night
Condensation
Moderate
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.
The ground is likely to be very wet after recent rain. Expect boggy approaches and choose a durable pitch carefully.
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 45–55 mph.Poor0View 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 45–55 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross basalt, which grips well when dry and can be very slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust45-55 mphRain4.5 mm
Main factorsgusts of 45–55 mphwet rock likelymuch of the route may be in cloud
Representative rock around the summit and along available routes
Volcaniclastic rockFoel Fras Volcanic Complex
Origin
Sedimentary and igneous
Broad rock-response group
Volcanic rock
Mapping
BGS Geology 50K · 1:50,000
Summit area
Volcanic rock in 88% of 17 BGS samples within 350 m
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Carneddau Aber Falls
volcanic rock, granite, gneiss or gabbro
Geological detail and BGS records
Mapped variation
5 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
Volcaniclastic rockFoel Fras Volcanic Complex576–813 m samplesSeen on Peak Carneddau Aber Falls
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
BasaltFoel Grach Basalt Formation932–1,053 m samplesSeen on Peak Carneddau Aber Falls
Basalt is a dark volcanic rock. It grips well when dry and can be very slippery when wet. It is often blocky and shattered, with loose rubble on ledges.
BGS record →
Route sample
MicrogranodioriteUnnamed Igneous Intrusion, OrdovicianAround 342 mSeen on Peak Carneddau Aber Falls
Granite is a coarse, crystalline rock. It has excellent friction when dry and clean and is fair when wet, but greasy where there is lichen or moss. It is generally solid, but weathers into rounded slabs and blocks, and loose granite grit on slabs can roll underfoot like ball bearings.
BGS record →
Route sample
TrachyandesiteUnnamed Igneous Intrusion, OrdovicianAround 450 mSeen on Peak Carneddau Aber Falls
Andesite is a hard volcanic rock. It grips well when dry and is fair when wet, though polished holds on popular routes get slippery. It is generally solid, but shattered in gullies and on broken ground.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup
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.
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 darkBetaNo sky forecast for this night yet. Moon and darkness times are shown separately.View forecastClose forecast
After dark: aurora and stargazing
Night beginning 2026-10-26. 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
No sky forecast for this night yet. Moon and darkness times are shown separately.
A bright moon is up all through the dark hours, washing out fainter stars and meteors.
Moon, darkness and meteor showers
Near-full moon, about 99% illuminated.
Full darkness: 26 Oct, 18:55 GMT to 27 Oct, 05:10 GMT.
Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.
Southern Taurids are active on this night. Activity may be much lower away from the peak.
Orionids are active on this night. Activity may be much lower away from the peak.
Northern Taurids are active on this night. Activity may be much lower away from the peak.
Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.
Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.
Darkness of the surroundings
Estimated darkness rank 906 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.
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 Garnedd Uchaf on Monday 26 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
A mixed day on Garnedd Uchaf, with burns likely to be in spate and drizzle clearing by midday.
Things to watch
Burns and rivers are likely to be in spate from the morning into the afternoon, so unbridged crossings could be difficult or impossible. Timings are rough. Turn back if a crossing looks unsafe.
Wind
On the summit expect a westerly wind of 15–25 mph for most of the day, with gusts of 25–35 mph at the windiest. Lower down on the open hillside it will be more like 5–15 mph. A wind like that will be noticeable on ridges and open tops, and you will chill quickly when you stop.
Cloud and visibility
The tops should stay clear of cloud all day.
Rain and ground
Drizzle at first, clearing by midday. Expect 2–5 mm in total. Some forecast models keep it drier in the morning. It will be wet underfoot after recent rain.
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. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 4:55pm, so allow time to get off the hill before dark, and carry a head torch.
Forecast confidence
It's still six days off and could change, so check again nearer the time.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 8.8 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.
Morning · 08:00–12:00
MixedSummit winds around 15-25 mph. Gusts around 25-35 mph are possible on exposed ground. Rain is forecast during this period. Some forecast models bring rain during the morning, while others keep it mostly dry.
50
Afternoon · 12:00–17:00
MixedRain eases compared with the morning. Summit winds around 15-25 mph. Gusts around 20-30 mph are possible on exposed ground.
50
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 55 mph and about 3 mm of rain.9Poor · 600 mView detailsHide details
Night beginning Tuesday 27 October 2026
Full overnight outlook
Not a night to camp on the open hill. Gusts reach about 55 mph around 900 m and nearer 40 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. Dry to pitch, then about 3 mm of rain overnight and into the morning, so expect to pack a wet tent. Overnight lows of about 5°C at 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 27 Oct, 17:00 GMT to 28 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m19 · very poor
Wind / gust
24 mph / 40 mph
Typical / low
6.8°C / 5.4°C · much of the night
In cloud
0% of modelled night
Condensation
Low
600 m9 · very poor
Wind / gust
28 mph / 48 mph
Typical / low
6.8°C / 5.4°C · much of the night
In cloud
0% of modelled night
Condensation
Low
900 m9 · very poor
Wind / gust
34 mph / 57 mph
Typical / low
5.6°C / 4.9°C · a brief spell
In cloud
13% 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.
Mixed conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 25–35 mph could throw you off balance on exposed moves and ridges. The rock around the summit is mostly volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross basalt, which grips well when dry and can be very slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust25-35 mphRain2.2 mm
Main concernwet rock likely
Representative rock around the summit and along available routes
Volcaniclastic rockFoel Fras Volcanic Complex
Origin
Sedimentary and igneous
Broad rock-response group
Volcanic rock
Mapping
BGS Geology 50K · 1:50,000
Summit area
Volcanic rock in 88% of 17 BGS samples within 350 m
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Carneddau Aber Falls
volcanic rock, granite, gneiss or gabbro
Geological detail and BGS records
Mapped variation
5 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
Volcaniclastic rockFoel Fras Volcanic Complex576–813 m samplesSeen on Peak Carneddau Aber Falls
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
BasaltFoel Grach Basalt Formation932–1,053 m samplesSeen on Peak Carneddau Aber Falls
Basalt is a dark volcanic rock. It grips well when dry and can be very slippery when wet. It is often blocky and shattered, with loose rubble on ledges.
BGS record →
Route sample
MicrogranodioriteUnnamed Igneous Intrusion, OrdovicianAround 342 mSeen on Peak Carneddau Aber Falls
Granite is a coarse, crystalline rock. It has excellent friction when dry and clean and is fair when wet, but greasy where there is lichen or moss. It is generally solid, but weathers into rounded slabs and blocks, and loose granite grit on slabs can roll underfoot like ball bearings.
BGS record →
Route sample
TrachyandesiteUnnamed Igneous Intrusion, OrdovicianAround 450 mSeen on Peak Carneddau Aber Falls
Andesite is a hard volcanic rock. It grips well when dry and is fair when wet, though polished holds on popular routes get slippery. It is generally solid, but shattered in gullies and on broken ground.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup
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.
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 darkBetaNo sky forecast for this night yet. Moon and darkness times are shown separately.View forecastClose forecast
After dark: aurora and stargazing
Night beginning 2026-10-27. 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
No sky forecast for this night yet. Moon and darkness times are shown separately.
A bright moon is up all through the dark hours, washing out fainter stars and meteors.
Moon, darkness and meteor showers
Near-full moon, about 96% illuminated.
Full darkness: 27 Oct, 18:50 GMT to 28 Oct, 05:10 GMT.
Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.
Southern Taurids are active on this night. Activity may be much lower away from the peak.
Orionids are active on this night. Activity may be much lower away from the peak.
Northern Taurids are active on this night. Activity may be much lower away from the peak.
Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.
Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.
Darkness of the surroundings
Estimated darkness rank 906 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.
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 Garnedd Uchaf on Tuesday 27 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
A poor day on the tops of Garnedd Uchaf, with strong, gusty winds and rain for much of the day.
Wind
On the summit expect a south-westerly wind of around 25–35 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 65–75 mph.
Cloud and visibility
Expect the summit to be in cloud for most of the day. The cloud base could be as low as 700–1000 m early in the morning. 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. Visibility may drop briefly in showers. Mist or fog is possible in the valleys early on, clearing by about 8am.
Rain and ground
Rain for much of the day. Expect 5–10 mm in total. It will be wet underfoot after recent rain.
Warmth and kit
On the tops it will be around 4 to 8°C, feeling like 0 to 4°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
Sunset is around 4:50pm, 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.
Morning · 08:00–12:00
PoorSummit 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.
21
Afternoon · 12:00–17:00
PoorWinds ease compared with the morning. Summit winds around 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Rain is forecast during this period.
40
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaA mixed night to camp, mainly because of the wind: gusts of about 30 mph.59Mixed · 600 mView detailsHide details
Night beginning Wednesday 28 October 2026
Full overnight outlook
A mixed night to camp, mainly because of the wind. Gusts reach about 30 mph on open ground, so peg out well and use the guylines. Look for shelter from the southwest. Expect a little rain, mostly early on, so you'll likely pitch in the rain. Overnight lows of about 4°C at 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 28 Oct, 17:00 GMT to 29 Oct, 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
12 mph / 22 mph
Typical / low
5.0°C / 4.8°C · several hours
In cloud
0% of modelled night
Condensation
Moderate
600 m59 · mixed
Wind / gust
14 mph / 26 mph
Typical / low
5.0°C / 4.8°C · several hours
In cloud
0% of modelled night
Condensation
Moderate
900 m59 · mixed
Wind / gust
17 mph / 31 mph
Typical / low
4.0°C / 3.6°C · much of the night
In cloud
20% of modelled night
Condensation
Moderate
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.
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.Poor0View 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 volcanic tuff, rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. On the usual routes up you may also cross basalt, which grips well when dry and can be very slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust40-50 mphRain5.6 mm
Main factorsgusts of 40–50 mphwet rock likelymuch of the route may be in cloud
Representative rock around the summit and along available routes
Volcaniclastic rockFoel Fras Volcanic Complex
Origin
Sedimentary and igneous
Broad rock-response group
Volcanic rock
Mapping
BGS Geology 50K · 1:50,000
Summit area
Volcanic rock in 88% of 17 BGS samples within 350 m
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Carneddau Aber Falls
volcanic rock, granite, gneiss or gabbro
Geological detail and BGS records
Mapped variation
5 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
Volcaniclastic rockFoel Fras Volcanic Complex576–813 m samplesSeen on Peak Carneddau Aber Falls
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
BasaltFoel Grach Basalt Formation932–1,053 m samplesSeen on Peak Carneddau Aber Falls
Basalt is a dark volcanic rock. It grips well when dry and can be very slippery when wet. It is often blocky and shattered, with loose rubble on ledges.
BGS record →
Route sample
MicrogranodioriteUnnamed Igneous Intrusion, OrdovicianAround 342 mSeen on Peak Carneddau Aber Falls
Granite is a coarse, crystalline rock. It has excellent friction when dry and clean and is fair when wet, but greasy where there is lichen or moss. It is generally solid, but weathers into rounded slabs and blocks, and loose granite grit on slabs can roll underfoot like ball bearings.
BGS record →
Route sample
TrachyandesiteUnnamed Igneous Intrusion, OrdovicianAround 450 mSeen on Peak Carneddau Aber Falls
Andesite is a hard volcanic rock. It grips well when dry and is fair when wet, though polished holds on popular routes get slippery. It is generally solid, but shattered in gullies and on broken ground.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup
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.
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 Garnedd Uchaf on Wednesday 28 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
