Select a day to replace the detailed forecast below. 8 forecast days are available here.
Confidence: Medium
Overall hill weather10/100Poor
Wind15-35 mph southwesterlyGusts35-45 mphFeels like2 to 6°CPrecipitationAround 10-20 mmCloud-free summit estimate10%Cloud base through day600-900 mFreezing levelAbove summitDaylightSunrise 07:02 · Sunset 19:18 · 12.3 hours daylight
The day on the hill
A wet day with extensive summit cloud on Chno Dearg: summit wind broadly 15-35 mph, with gusts 35-45 mph at times (strong winds).
Things to watch
Possible spate risk through the day and overnight, with forecast rain and subsequent runoff. Risk may continue beyond the daytime period shown. Timings are approximate, not a guarantee of safe crossings afterwards. Burns and unbridged crossings may rise quickly. Turn back if a crossing looks unsafe.
Wind & exposure
Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops.
Cloud & views
Cloud base mostly around 600–900 m through daylight. Cloud is likely to cover the top for most or all of daylight, with no dependable break.
Cloud may hang lower on southwestern slopes and lift somewhat on the northeastern side, but local terrain can differ. Very little direct sunshine is likely, with extensive cloud.
Drizzle is forecast for much of the day. The forecast total is around 10-20 mm, but local amounts will vary.
Forecast models differ on summit wind strength: around 22-33 mph at walker height, with gusts 31-46 mph. Exposed tops may feel chilly in the wind.
A windproof layer will help, with an extra warm layer for stops. If clothing gets wet, you can cool more quickly.
Keep a dry warm layer protected. Buffeting may affect balance on exposed ground, particularly near ridges and edges.
Forecast confidence
Rain is forecast during late afternoon and evening, but models differ considerably on the amount.
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 20-30 mph. Gusts around 35-45 mph are possible on exposed ground. Buffeting may affect balance on exposed ground, particularly near ridges and edges. Rain is forecast during this period.
2/100
Afternoon · 12:00–17:00
PoorSummit winds around 15-25 mph. Gusts around 30-40 mph are possible on exposed ground. Rain is forecast during this period.
17/100
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaGusts near 30 mph make meaningful shelter important.39/100Poor · 600 mView detailsHide details
Night beginning Tuesday 22 September 2026
Full overnight outlook
Open-hillside camping looks poor overall around 600 m (39/100). Open-ground gusts may reach about 30 mph. Seek meaningful shelter. Peak gusts range from about 20 mph at 300 m to 30 mph at 900 m. Wind direction may change substantially during the night. Shelter that works at dusk may be less effective later. Roughly 30.5 mm is forecast overnight, with rain liable to affect both pitching and packing up. Pitches near 900 m may spend part of the night in cloud, bringing damp conditions and poor visibility while cloud is present. Condensation risk is high near 300, 600 and 900 m. Ventilation will matter. The coldest temperature falls from about 6.5°C at 300 m to 4.4°C at 900 m.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 22 Sep, 17:00 BST to 23 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m39/100 · poor
Wind / gust
11 mph / 22 mph
Typical / low
8.8°C / 6.5°C · much of the night
In cloud
0% of modelled night
Condensation
High
600 m39/100 · poor
Wind / gust
13 mph / 26 mph
Typical / low
8.8°C / 6.5°C · much of the night
In cloud
0% of modelled night
Condensation
High
900 m39/100 · poor
Wind / gust
15 mph / 30 mph
Typical / low
7.2°C / 4.4°C · a brief spell
In cloud
100% 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.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 40 mph may affect balance on exposed rock.Poor0/100View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Conditions for exposed scrambling look very poor (0/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Pelite (Loch Treig Schist And Quartzite Formation). Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Representative samples along available mapped routes also include Metaquartz-arenite, Pelite and calcsilicate-rock, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 40 mph. Crosswinds can make exposed ridges substantially more serious. Cloud may also make route-finding and retreat harder.
Rock surfaceWet rock likelyPeak gust40 mphRain11.6 mm
Main factorsgusts around 40 mphwet rock likelymuch of the route may be in cloud
Mapped rock across the summit and available routes
PeliteLoch Treig Schist And Quartzite Formation
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Summit-point mapping plus representative BGS bedrock samples along available GPX routes. These are not continuous geological surveys; contacts, superficial deposits and the exposed rock on individual holds may differ.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Stob Coire Sgriodain and Chno Dearg
quartzite, sandstone or gritstone, psammite, pelite or semipelite
Geological detail and BGS records
Mapped variation
3 rock types appear across the available route samples
The summit type remains the forecast's cautious rock-response reference. Other mapped types show where conditions may behave differently elsewhere on the mountain.
Summit mapping
PeliteLoch Treig Schist And Quartzite Formation435–1,046 m samplesSeen on Stob Coire Sgriodain and Chno Dearg
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery.
BGS record →
Route sample
Metaquartz-areniteReservoir Quartzite MemberAround 643 mSeen on Stob Coire Sgriodain and Chno Dearg
Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully.
BGS record →
Route sample
Pelite and calcsilicate-rockLeven Schist FormationAround 844 mSeen on Stob Coire Sgriodain and Chno Dearg
Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.
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.
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 Chno Dearg on Tuesday 22 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
Wind10-25 mph northwesterlyGusts25-35 mphFeels like-4 to 0°CPrecipitationLittle or noneCloud-free summit estimate60%Cloud base through day600-1,800 mFreezing levelAbove summitDaylightSunrise 07:04 · Sunset 19:16 · 12.2 hours daylight
The day on the hill
On Chno Dearg: summit wind broadly 10-25 mph, with gusts 25-35 mph at times (a fresh breeze).
Things to watch
High spate risk during the morning, after earlier rain. Timings are approximate, not a guarantee of safe crossings afterwards. Burns and unbridged crossings may become difficult or impassable. Turn back if a crossing looks unsafe.
Cloud & views
Cloud base around 600–900 m in the morning, lifting to 1000–1300 m around midday and 1500–1800 m by late afternoon. Summit cloud is extensive early, becoming less frequent later.
Cloud-height uncertainty could put the summit in or out of cloud. Clear spells may be difficult to time.
Cloud may hang lower on northwestern slopes and lift somewhat on the southeastern side, but local terrain can differ. Sunny spells are possible away from summit cloud, but may not reach the top while it is in cloud.
Rain & temperature
The ground is likely to be wet after recent rain. Little or no rain is forecast.
Cold on exposed tops: air temperature broadly 2 to 6°C, feeling around -4 to 0°C in the wind.
Forecast confidence
Cloud height remains uncertain, especially where it is close to summit level. Keep windproof and warm layers readily available.
Cloud-height uncertainty could put the summit in or out of cloud, even where forecasts agree on the wider cloud cover.
Cloud-free timing: Around 5% early, improving to around 95% later.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 5.3 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.
Morning · 08:00–12:00
MixedSummit winds around 15-25 mph. Gusts around 25-35 mph are possible on exposed ground. Summit cloud is more persistent early in this period, with better prospects later.
50/100
Afternoon · 12:00–17:00
GoodSummit winds around 10-20 mph. Gusts around 15-25 mph are possible on exposed ground.
84/100
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaA cold night is forecast near 900 m, with the cold lasting much of the night.85/100Excellent · 600 mView detailsHide details
Night beginning Wednesday 23 September 2026
Full overnight outlook
Open-hillside camping looks promising overall around 600 m (85/100). A lower pitch near 300 m looks more comfortable. Conditions are less suitable by 900 m. It may be breezy on open ground, with gusts near 20 mph. Peak gusts range from about 15 mph at 300 m to 20 mph at 900 m. Little overnight rain is forecast. Pitches near 900 m may spend part of the night in cloud, bringing damp conditions and poor visibility while cloud is present.
Clear spells may allow a view of the Moon. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 23 Sep, 17:00 BST to 24 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m87/100 · promising
Wind / gust
8 mph / 15 mph
Typical / low
6.4°C / 5.3°C · much of the night
In cloud
0% of modelled night
Condensation
Moderate
600 m85/100 · promising
Wind / gust
10 mph / 18 mph
Typical / low
6.4°C / 5.3°C · much of the night
In cloud
0% of modelled night
Condensation
Moderate
900 m59/100 · mixed
Wind / gust
11 mph / 21 mph
Typical / low
4.7°C / 4.4°C · much of the night
In cloud
40% 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.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaRock may be damp or still drying. Gusts near 30 mph may affect balance on exposed rock.Poor33/100View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Conditions for exposed scrambling look poor (33/100). Recent rain may leave seepage and damp rock, especially on shaded sections. The mapped summit rock is Pelite (Loch Treig Schist And Quartzite Formation). Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Representative samples along available mapped routes also include Metaquartz-arenite, Pelite and calcsilicate-rock, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 30 mph. Crosswinds can make exposed ridges substantially more serious.
Rock surfaceDry overhead; seepage uncertainPeak gust30 mphRainPossible · 95%
Main factorsgusts around 30 mphdamp or incompletely dried rock possible
Mapped rock across the summit and available routes
PeliteLoch Treig Schist And Quartzite Formation
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Summit-point mapping plus representative BGS bedrock samples along available GPX routes. These are not continuous geological surveys; contacts, superficial deposits and the exposed rock on individual holds may differ.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Stob Coire Sgriodain and Chno Dearg
quartzite, sandstone or gritstone, psammite, pelite or semipelite
Geological detail and BGS records
Mapped variation
3 rock types appear across the available route samples
The summit type remains the forecast's cautious rock-response reference. Other mapped types show where conditions may behave differently elsewhere on the mountain.
Summit mapping
PeliteLoch Treig Schist And Quartzite Formation435–1,046 m samplesSeen on Stob Coire Sgriodain and Chno Dearg
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery.
BGS record →
Route sample
Metaquartz-areniteReservoir Quartzite MemberAround 643 mSeen on Stob Coire Sgriodain and Chno Dearg
Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully.
BGS record →
Route sample
Pelite and calcsilicate-rockLeven Schist FormationAround 844 mSeen on Stob Coire Sgriodain and Chno Dearg
Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.
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.
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 Chno Dearg on Wednesday 23 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
Wind30-45 mph southwesterlyGusts50-60 mphFeels like-6 to -2°CPrecipitationAround 2-5 mmCloud-free summit estimate75%Cloud base through day1,400-1,700 mFreezing levelAbove summitDaylightSunrise 07:06 · Sunset 19:13 · 12.1 hours daylight
The day on the hill
Strong gusts on Chno Dearg: summit wind broadly 30-45 mph, with gusts 50-60 mph at times (gale-force mean winds at times).
Wind & exposure
Much calmer lower down - generally 15-25 mph in the valley, rising towards the tops. Gusts may knock you off balance on exposed ground, even between spells of lighter wind.
Cloud & views
Cloud base mostly around 1400–1700 m through daylight. The top is likely to drift in and out of cloud, with the best chance of a view from early morning into around midday.
Cloud may hang lower on southwestern slopes and lift somewhat on the northeastern side, but local terrain can differ. Sunny spells are possible away from summit cloud, but may not reach the top while it is in cloud.
Drizzle is forecast at times. The forecast total is around 2-5 mm, but local amounts will vary.
Cold on exposed tops: air temperature broadly 2 to 6°C, feeling around -6 to -2°C in the wind. Forecast models differ on summit wind strength: around 34-46 mph at walker height, with gusts 48-64 mph.
Keep windproof and warm layers readily available. If clothing gets wet, you can cool more quickly.
Keep a dry warm layer protected.
Rain & temperature
The ground is likely to be wet after recent rain.
Forecast confidence
Forecast models differ on whether meaningful rain reaches the hills during the afternoon and evening.
Cloud-free timing: Around 95% early, falling to around 50% later.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 5 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 10-20 mph early in the morning, strengthening to 30-40 mph later. Gusts around 45-55 mph are possible on exposed ground. Gusts may knock you off balance on exposed ground, even between spells of lighter wind.
41/100
Afternoon · 12:00–17:00
PoorWinds strengthen compared with the morning. Summit winds around 35-45 mph. Gusts around 50-60 mph are possible on exposed ground. Gusts may knock you off balance on exposed ground, even between spells of lighter wind. 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.
31/100
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaExposed camping is not recommended near 600 and 900 m: gusts may reach about 60 mph. Sustained winds may reach about 40 mph at times. Choose an alternative off the exposed hill. Do not rely on finding shelter after setting out.9/100Poor · 600 mView detailsHide details
Night beginning Thursday 24 September 2026
Full overnight outlook
Exposed camping is not recommended near 600 and 900 m: gusts may reach about 60 mph. Sustained winds may reach about 40 mph at times. Choose an alternative off the exposed hill. Do not rely on finding shelter after setting out. Open-hillside camping looks very poor overall around 600 m (9/100). Peak gusts range from about 40 mph at 300 m to 60 mph at 900 m. Roughly 8.2 mm is forecast overnight, including rain around pitching time. Pitches near 600 and 900 m may spend part of the night in cloud, bringing damp conditions and poor visibility while cloud is present. Condensation risk is high near 600 and 900 m. Ventilation will matter. The coldest temperature falls from about 7.6°C at 300 m to 5.1°C at 900 m.
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: 24 Sep, 17:00 BST to 25 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m39/100 · poor
Wind / gust
23 mph / 41 mph
Typical / low
9.0°C / 7.6°C · much of the night
In cloud
0% of modelled night
Condensation
Moderate
600 m9/100 · very poor
Wind / gust
28 mph / 49 mph
Typical / low
8.4°C / 7.1°C · much of the night
In cloud
60% of modelled night
Condensation
High
900 m9/100 · very poor
Wind / gust
33 mph / 58 mph
Typical / low
6.1°C / 5.1°C · much of the night
In cloud
93% 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.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 55 mph may affect balance on exposed rock.Poor0/100View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Conditions for exposed scrambling look very poor (0/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Pelite (Loch Treig Schist And Quartzite Formation). Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Representative samples along available mapped routes also include Metaquartz-arenite, Pelite and calcsilicate-rock, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 55 mph. Crosswinds can make exposed ridges substantially more serious.
Rock surfaceWet rock likelyPeak gust56 mphRain1.5 mm
Main factorsgusts around 55 mphwet rock likely
Mapped rock across the summit and available routes
PeliteLoch Treig Schist And Quartzite Formation
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Summit-point mapping plus representative BGS bedrock samples along available GPX routes. These are not continuous geological surveys; contacts, superficial deposits and the exposed rock on individual holds may differ.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Stob Coire Sgriodain and Chno Dearg
quartzite, sandstone or gritstone, psammite, pelite or semipelite
Geological detail and BGS records
Mapped variation
3 rock types appear across the available route samples
The summit type remains the forecast's cautious rock-response reference. Other mapped types show where conditions may behave differently elsewhere on the mountain.
Summit mapping
PeliteLoch Treig Schist And Quartzite Formation435–1,046 m samplesSeen on Stob Coire Sgriodain and Chno Dearg
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery.
BGS record →
Route sample
Metaquartz-areniteReservoir Quartzite MemberAround 643 mSeen on Stob Coire Sgriodain and Chno Dearg
Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully.
BGS record →
Route sample
Pelite and calcsilicate-rockLeven Schist FormationAround 844 mSeen on Stob Coire Sgriodain and Chno Dearg
Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.
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.
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 Chno Dearg on Thursday 24 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
Wind20-30 mph southwesterlyGusts35-45 mphFeels like-4 to 0°CPrecipitationAround 2-5 mmCloud-free summit estimate20%Cloud base through day700-1,200 mFreezing levelAbove summitDaylightSunrise 07:08 · Sunset 19:10 · 12.0 hours daylight
The day on the hill
A wet day with extensive summit cloud on Chno Dearg: summit wind broadly 20-30 mph, with gusts 35-45 mph at times (strong winds).
Wind & exposure
Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops.
Cloud & views
Cloud base around 700–1000 m in the morning, then around 900–1200 m around midday and 700–1000 m by late afternoon. Summit cloud is likely, but brief clear spells remain possible if the cloud sits higher than expected.
Cloud-height uncertainty could put the summit in or out of cloud. Clear spells may be difficult to time.
Cloud may hang lower on southwestern slopes and lift somewhat on the northeastern side, but local terrain can differ. Any sunshine may be confined to lower ground or breaks away from the summit.
Drizzle is forecast for much of the day, with some passing showers too. The forecast total is around 2-5 mm, but local amounts will vary.
Cold on exposed tops: air temperature broadly 2 to 6°C, feeling around -4 to 0°C in the wind. Forecast models differ on summit wind strength: around 17-35 mph at walker height, with gusts 25-49 mph.
Rain & temperature
The ground is likely to be wet after recent rain.
Forecast confidence
Cloud height remains uncertain, especially where it is close to summit level. Keep windproof and warm layers readily available.
If clothing gets wet, you can cool more quickly. Keep a dry warm layer protected.
Buffeting may affect balance on exposed ground, particularly near ridges and edges. Some forecast models bring rain during late afternoon and evening, while others keep it mostly dry.
Cloud-free timing: Best around midday at about 30%, compared with around 15% early and 10% later.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 9.7 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.
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 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Buffeting may affect balance on exposed ground, particularly near ridges and edges. Rain is forecast during this period.
27/100
Afternoon · 12:00–17:00
PoorSummit winds around 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Buffeting may affect balance on exposed ground, particularly near ridges and edges. Rain is forecast during this period.
24/100
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaExposed camping is not recommended near 900 m: gusts may reach about 45 mph. Sustained winds may reach about 30 mph at times. Lower sheltered ground may be less exposed, but this forecast does not confirm a suitable pitch or a safe approach. Check its overnight conditions separately.39/100Poor · 600 mView detailsHide details
Night beginning Friday 25 September 2026
Full overnight outlook
Exposed camping is not recommended near 900 m: gusts may reach about 45 mph. Sustained winds may reach about 30 mph at times. Lower sheltered ground may be less exposed, but this forecast does not confirm a suitable pitch or a safe approach. Check its overnight conditions separately. Open-hillside camping looks poor overall around 600 m (39/100). Peak gusts range from about 30 mph at 300 m to 45 mph at 900 m. Around 3.4 mm is forecast, with rain liable to affect both pitching and packing up. Pitches near 600 and 900 m may spend part of the night in cloud, bringing damp conditions and poor visibility while cloud is present. Condensation risk is high near 600 and 900 m. Ventilation will matter. The coldest temperature falls from about 6.7°C at 300 m to 4.2°C at 900 m.
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: 25 Sep, 17:00 BST to 26 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m59/100 · mixed
Wind / gust
20 mph / 30 mph
Typical / low
7.7°C / 6.7°C · much of the night
In cloud
0% of modelled night
Condensation
Moderate
600 m39/100 · poor
Wind / gust
24 mph / 36 mph
Typical / low
7.2°C / 6.2°C · much of the night
In cloud
93% of modelled night
Condensation
High
900 m19/100 · very poor
Wind / gust
29 mph / 43 mph
Typical / low
5.3°C / 4.2°C · several hours
In cloud
100% 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.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 35 mph may affect balance on exposed rock.Poor0/100View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Conditions for exposed scrambling look very poor (0/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Pelite (Loch Treig Schist And Quartzite Formation). Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Representative samples along available mapped routes also include Metaquartz-arenite, Pelite and calcsilicate-rock, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 35 mph. Crosswinds can make exposed ridges substantially more serious. Cloud may also make route-finding and retreat harder.
Rock surfaceWet rock likelyPeak gust37 mphRain1.8 mm
Main factorsgusts around 35 mphwet rock likelymuch of the route may be in cloud
Mapped rock across the summit and available routes
PeliteLoch Treig Schist And Quartzite Formation
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Summit-point mapping plus representative BGS bedrock samples along available GPX routes. These are not continuous geological surveys; contacts, superficial deposits and the exposed rock on individual holds may differ.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Stob Coire Sgriodain and Chno Dearg
quartzite, sandstone or gritstone, psammite, pelite or semipelite
Geological detail and BGS records
Mapped variation
3 rock types appear across the available route samples
The summit type remains the forecast's cautious rock-response reference. Other mapped types show where conditions may behave differently elsewhere on the mountain.
Summit mapping
PeliteLoch Treig Schist And Quartzite Formation435–1,046 m samplesSeen on Stob Coire Sgriodain and Chno Dearg
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery.
BGS record →
Route sample
Metaquartz-areniteReservoir Quartzite MemberAround 643 mSeen on Stob Coire Sgriodain and Chno Dearg
Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully.
BGS record →
Route sample
Pelite and calcsilicate-rockLeven Schist FormationAround 844 mSeen on Stob Coire Sgriodain and Chno Dearg
Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.
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.
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 Chno Dearg on Friday 25 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
Wind30-45 mph southwesterlyGusts50-60 mphFeels like-4 to 0°CPrecipitationAround 5-10 mmCloud-free summit estimate10%Cloud base through day400-1,000 mFreezing levelAbove summitDaylightSunrise 07:10 · Sunset 19:07 · 11.9 hours daylight
The day on the hill
Strong gusts and frequent summit cloud on Chno Dearg: summit wind broadly 30-45 mph, with gusts 50-60 mph at times (gale-force mean winds at times).
Wind & exposure
Much calmer lower down - generally 10-20 mph in the valley, rising towards the tops.
Cloud & views
Cloud base around 500–800 m in the morning, then around 700–1000 m around midday and 400–700 m by late afternoon. Summit cloud is likely, but brief clear spells remain possible if the cloud sits higher than expected.
Cloud-height uncertainty could put the summit in or out of cloud. Clear spells may be difficult to time.
Cloud may hang lower on southwestern slopes and lift somewhat on the northeastern side, but local terrain can differ. Any sunshine may be confined to lower ground or breaks away from the summit.
Drizzle is forecast for much of the day, with some passing showers too. The forecast total is around 5-10 mm, but local amounts will vary.
Cold on exposed tops: air temperature broadly 2 to 6°C, feeling around -4 to 0°C in the wind. Forecast models differ on summit wind strength: around 27-48 mph at walker height, with gusts 37-67 mph.
Rain & temperature
The ground is likely to be wet after recent rain.
Forecast confidence
Cloud height remains uncertain, especially where it is close to summit level. Keep windproof and warm layers readily available.
If clothing gets wet, you can cool more quickly. Keep a dry warm layer protected.
Walking into the wind is likely to be arduous, with buffeting that can knock you off balance. Summit wind could be roughly 27-48 mph, which changes how difficult exposed walking may feel.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 3.6 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 25-35 mph. Gusts around 35-45 mph are possible on exposed ground. Buffeting may affect balance on exposed ground, particularly near ridges and edges. Rain is forecast during this period.
21/100
Afternoon · 12:00–17:00
PoorWinds strengthen compared with the morning. Summit winds around 30-40 mph. Gusts around 50-60 mph are possible on exposed ground. Gusts may knock you off balance on exposed ground, even between spells of lighter wind. Rain is forecast during this period. Some forecast models bring rain during the afternoon, while others keep it mostly dry.
1/100
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaExposed camping is not recommended near 300, 600 and 900 m: gusts may reach about 60 mph. Sustained winds may reach about 45 mph at times. Choose an alternative off the exposed hill. Do not rely on finding shelter after setting out.9/100Poor · 600 mView detailsHide details
Night beginning Saturday 26 September 2026
Full overnight outlook
Exposed camping is not recommended near 300, 600 and 900 m: gusts may reach about 60 mph. Sustained winds may reach about 45 mph at times. Choose an alternative off the exposed hill. Do not rely on finding shelter after setting out. Open-hillside camping looks very poor overall around 600 m (9/100). Peak gusts range from about 45 mph at 300 m to 60 mph at 900 m. Roughly 28.3 mm is forecast overnight, with rain liable to affect both pitching and packing up. Pitches near 600 and 900 m may spend part of the night in cloud, bringing damp conditions and poor visibility while cloud is present. Condensation risk is high near 600 and 900 m. Ventilation will matter. The coldest temperature falls from about 8.8°C at 300 m to 6°C at 900 m.
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: 26 Sep, 17:00 BST to 27 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m19/100 · very poor
Wind / gust
27 mph / 43 mph
Typical / low
10.4°C / 8.8°C · several hours
In cloud
0% of modelled night
Condensation
Moderate
600 m9/100 · very poor
Wind / gust
33 mph / 51 mph
Typical / low
9.7°C / 7.8°C · much of the night
In cloud
93% of modelled night
Condensation
High
900 m9/100 · very poor
Wind / gust
38 mph / 60 mph
Typical / low
7.7°C / 6.0°C · much of the night
In cloud
100% 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.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 55 mph may affect balance on exposed rock.Poor0/100View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Conditions for exposed scrambling look very poor (0/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Pelite (Loch Treig Schist And Quartzite Formation). Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Representative samples along available mapped routes also include Metaquartz-arenite, Pelite and calcsilicate-rock, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 55 mph. Crosswinds can make exposed ridges substantially more serious. Cloud may also make route-finding and retreat harder.
Rock surfaceWet rock likelyPeak gust57 mphRain4.4 mm
Main factorsgusts around 55 mphwet rock likelymuch of the route may be in cloud
Mapped rock across the summit and available routes
PeliteLoch Treig Schist And Quartzite Formation
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Summit-point mapping plus representative BGS bedrock samples along available GPX routes. These are not continuous geological surveys; contacts, superficial deposits and the exposed rock on individual holds may differ.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Stob Coire Sgriodain and Chno Dearg
quartzite, sandstone or gritstone, psammite, pelite or semipelite
Geological detail and BGS records
Mapped variation
3 rock types appear across the available route samples
The summit type remains the forecast's cautious rock-response reference. Other mapped types show where conditions may behave differently elsewhere on the mountain.
Summit mapping
PeliteLoch Treig Schist And Quartzite Formation435–1,046 m samplesSeen on Stob Coire Sgriodain and Chno Dearg
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery.
BGS record →
Route sample
Metaquartz-areniteReservoir Quartzite MemberAround 643 mSeen on Stob Coire Sgriodain and Chno Dearg
Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully.
BGS record →
Route sample
Pelite and calcsilicate-rockLeven Schist FormationAround 844 mSeen on Stob Coire Sgriodain and Chno Dearg
Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.
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.
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 Chno Dearg on Saturday 26 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
Wind20-30 mph southwesterlyGusts30-40 mphFeels like-4 to 0°CPrecipitationAround 2-5 mmCloud-free summit estimate50%Cloud base through day900-1,600 mFreezing levelAbove summitDaylightSunrise 07:13 · Sunset 19:05 · 11.9 hours daylight
The day on the hill
A wet day with extensive summit cloud on Chno Dearg: summit wind broadly 20-30 mph, with gusts 30-40 mph at times (strong winds). Visibility may drop briefly in showers.
Things to watch
High spate risk through much of the day and into the night, with recent and forecast rain and subsequent runoff. Risk may continue beyond the daytime period shown. Timings are approximate, not a guarantee of safe crossings afterwards. Burns and unbridged crossings may become difficult or impassable. Turn back if a crossing looks unsafe.
Wind & exposure
Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops.
Cloud & views
Cloud base around 1300–1600 m through the morning, lowering to 900–1200 m by late afternoon. The top is likely to drift in and out of cloud, with the best chance of a view from late morning into midday.
Cloud-height uncertainty could put the summit in or out of cloud. Clear spells may be difficult to time.
Cloud may hang lower on southwestern slopes and lift somewhat on the northeastern side, but local terrain can differ. Sunny spells are possible away from summit cloud, but may not reach the top while it is in cloud.
Drizzle is forecast for much of the day, with some passing showers too. The forecast total is around 2-5 mm, but local amounts will vary.
Cold on exposed tops: air temperature broadly 0 to 4°C, feeling around -4 to 0°C in the wind. Forecast models differ on summit wind strength: around 20-30 mph at walker height, with gusts 29-41 mph.
Rain & temperature
The ground is likely to be wet after recent rain.
Forecast confidence
Cloud height remains uncertain, especially where it is close to summit level. Keep windproof and warm layers readily available.
If clothing gets wet, you can cool more quickly. Keep a dry warm layer protected.
Buffeting may affect balance on exposed ground, particularly near ridges and edges. Forecast models differ on whether meaningful rain reaches the hills during the morning.
Cloud-free timing: Around 45% early, falling to around 35% later.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 11 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 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Buffeting may affect balance on exposed ground, particularly near ridges and edges. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period. Rain is possible during the morning, but forecast models disagree on whether it will fall. Rain is possible during the main walking period, but its timing may shift by several hours.
39/100
Afternoon · 12:00–17:00
PoorSummit winds around 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Buffeting may affect balance on exposed ground, particularly near ridges and edges. Summit cloud becomes more persistent later. Rain is forecast during this period. Rain is possible during the main walking period, but its timing may shift by several hours.
18/100
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaGusts near 30 mph make meaningful shelter important.54/100Mixed · 600 mView detailsHide details
Night beginning Sunday 27 September 2026
Full overnight outlook
Open-hillside camping looks mixed overall around 600 m (54/100). Open-ground gusts may reach about 30 mph. Seek meaningful shelter. Peak gusts range from about 25 mph at 300 m to 30 mph at 900 m. A little rain may coincide with pitching or packing up. Pitches near 600 and 900 m may spend part of the night in cloud, bringing damp conditions and poor visibility while cloud is present. Condensation risk is high near 300, 600 and 900 m. Ventilation will matter. The coldest temperature falls from about 6.5°C at 300 m to 3.9°C at 900 m.
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: 27 Sep, 17:00 BST to 28 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m64/100 · reasonable
Wind / gust
13 mph / 23 mph
Typical / low
6.7°C / 6.5°C · much of the night
In cloud
0% of modelled night
Condensation
High
600 m54/100 · mixed
Wind / gust
15 mph / 28 mph
Typical / low
6.0°C / 5.8°C · much of the night
In cloud
73% of modelled night
Condensation
High
900 m54/100 · mixed
Wind / gust
18 mph / 32 mph
Typical / low
4.0°C / 3.9°C · much of the night
In cloud
73% 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.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 35 mph may affect balance on exposed rock.Poor0/100View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Conditions for exposed scrambling look very poor (0/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Pelite (Loch Treig Schist And Quartzite Formation). Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Representative samples along available mapped routes also include Metaquartz-arenite, Pelite and calcsilicate-rock, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 35 mph. Crosswinds can make exposed ridges substantially more serious. Cloud may also make route-finding and retreat harder.
Rock surfaceWet rock likelyPeak gust36 mphRain4.6 mm
Main factorsgusts around 35 mphwet rock likelymuch of the route may be in cloud
Mapped rock across the summit and available routes
PeliteLoch Treig Schist And Quartzite Formation
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Summit-point mapping plus representative BGS bedrock samples along available GPX routes. These are not continuous geological surveys; contacts, superficial deposits and the exposed rock on individual holds may differ.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Stob Coire Sgriodain and Chno Dearg
quartzite, sandstone or gritstone, psammite, pelite or semipelite
Geological detail and BGS records
Mapped variation
3 rock types appear across the available route samples
The summit type remains the forecast's cautious rock-response reference. Other mapped types show where conditions may behave differently elsewhere on the mountain.
Summit mapping
PeliteLoch Treig Schist And Quartzite Formation435–1,046 m samplesSeen on Stob Coire Sgriodain and Chno Dearg
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery.
BGS record →
Route sample
Metaquartz-areniteReservoir Quartzite MemberAround 643 mSeen on Stob Coire Sgriodain and Chno Dearg
Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully.
BGS record →
Route sample
Pelite and calcsilicate-rockLeven Schist FormationAround 844 mSeen on Stob Coire Sgriodain and Chno Dearg
Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.
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.
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 Chno Dearg on Sunday 27 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
Wind10-25 mph southerlyGusts20-30 mphFeels like-6 to -2°CPrecipitationLittle or noneCloud-free summit estimate80%Cloud base through day900-1,900 mFreezing levelAbove summitDaylightSunrise 07:15 · Sunset 19:02 · 11.8 hours daylight
The day on the hill
Little rain and limited summit cloud on Chno Dearg: summit wind broadly 10-25 mph, with gusts 20-30 mph at times (a moderate breeze).
Cloud & views
Cloud base around 900–1200 m in the morning, then around 1600–1900 m around midday and 1400–1700 m by late afternoon. Summit cloud is extensive early, becoming less frequent later.
Cloud-height uncertainty could put the summit in or out of cloud. Clear spells may be difficult to time.
Sunny spells are possible away from summit cloud, but may not reach the top while it is in cloud.
Rain & temperature
The ground is likely to be wet after recent rain. Little or no rain is forecast.
Cold on exposed tops: air temperature broadly 0 to 4°C, feeling around -6 to -2°C in the wind. Forecast models differ on summit wind strength.
Treat the wind figures as a guide.
Forecast confidence
Cloud height remains uncertain, especially where it is close to summit level. Keep windproof and warm layers readily available.
Overall confidence is unavailable: insufficient comparable wind, rain guidance.
Cloud-free timing: Cloudy early, clearing later.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 5.9 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.
Morning · 08:00–12:00
MixedSummit winds around 10-20 mph. Gusts around 20-30 mph are possible on exposed ground. Summit cloud is more persistent early in this period, with better prospects later.
60/100
Afternoon · 12:00–17:00
ExcellentSummit winds around 10-20 mph. Gusts around 15-25 mph are possible on exposed ground.
92/100
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaExposed camping is not recommended near 300, 600 and 900 m: gusts may reach about 60 mph. Sustained winds may reach about 40 mph at times. Choose an alternative off the exposed hill. Do not rely on finding shelter after setting out.9/100Poor · 600 mView detailsHide details
Night beginning Monday 28 September 2026
Full overnight outlook
Exposed camping is not recommended near 300, 600 and 900 m: gusts may reach about 60 mph. Sustained winds may reach about 40 mph at times. Choose an alternative off the exposed hill. Do not rely on finding shelter after setting out. Open-hillside camping looks very poor overall around 600 m (9/100). Peak gusts range from about 40 mph at 300 m to 60 mph at 900 m. Around 1.1 mm is forecast, including rain around pack-up. Pitches near 900 m may spend part of the night in cloud, bringing damp conditions and poor visibility while cloud is present. Condensation risk is high near 900 m. Ventilation will matter. The coldest temperature falls from about 6.7°C at 300 m to 4.4°C at 900 m.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 28 Sep, 17:00 BST to 29 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m19/100 · very poor
Wind / gust
15 mph / 42 mph
Typical / low
8.0°C / 6.7°C · much of the night
In cloud
0% of modelled night
Condensation
Low
600 m9/100 · very poor
Wind / gust
18 mph / 50 mph
Typical / low
7.2°C / 6.7°C · much of the night
In cloud
7% of modelled night
Condensation
Moderate
900 m9/100 · very poor
Wind / gust
21 mph / 59 mph
Typical / low
5.2°C / 4.4°C · several hours
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 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.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaRock may be damp or still drying.Mixed65/100View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Conditions for exposed scrambling look fair (65/100). Recent rain may leave seepage and damp rock, especially on shaded sections. The mapped summit rock is Pelite (Loch Treig Schist And Quartzite Formation). Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Representative samples along available mapped routes also include Metaquartz-arenite, Pelite and calcsilicate-rock, so rock character and wet-weather behaviour may change across the mountain.
Rock surfaceDry overhead; seepage uncertainPeak gust26 mphRain0.0 mm
Main concerndamp or incompletely dried rock possible
Mapped rock across the summit and available routes
PeliteLoch Treig Schist And Quartzite Formation
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Summit-point mapping plus representative BGS bedrock samples along available GPX routes. These are not continuous geological surveys; contacts, superficial deposits and the exposed rock on individual holds may differ.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Stob Coire Sgriodain and Chno Dearg
quartzite, sandstone or gritstone, psammite, pelite or semipelite
Geological detail and BGS records
Mapped variation
3 rock types appear across the available route samples
The summit type remains the forecast's cautious rock-response reference. Other mapped types show where conditions may behave differently elsewhere on the mountain.
Summit mapping
PeliteLoch Treig Schist And Quartzite Formation435–1,046 m samplesSeen on Stob Coire Sgriodain and Chno Dearg
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery.
BGS record →
Route sample
Metaquartz-areniteReservoir Quartzite MemberAround 643 mSeen on Stob Coire Sgriodain and Chno Dearg
Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully.
BGS record →
Route sample
Pelite and calcsilicate-rockLeven Schist FormationAround 844 mSeen on Stob Coire Sgriodain and Chno Dearg
Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.
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.
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 Chno Dearg on Monday 28 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
Wind40-55 mph southeasterlyGusts65-75 mphFeels like-6 to -2°CPrecipitationAround 5-10 mmCloud-free summit estimate55%Cloud base through day600-1,600 mFreezing levelAbove summitDaylightSunrise 07:17 · Sunset 18:59 · 11.7 hours daylight
The day on the hill
Strong gusts on Chno Dearg: summit wind broadly 40-55 mph, with gusts 65-75 mph at times (gale-force mean winds at times).
Wind & exposure
Much calmer lower down - generally 10-20 mph in the valley, rising towards the tops.
Cloud & views
Cloud base around 600–900 m in the morning, lifting to 1200–1500 m around midday and 1300–1600 m by late afternoon. Summit cloud is extensive early, becoming less frequent later.
Cloud-height uncertainty could put the summit in or out of cloud. Clear spells may be difficult to time.
Cloud may hang lower on southeastern slopes and lift somewhat on the northwestern side, but local terrain can differ. Sunny spells are possible away from summit cloud, but may not reach the top while it is in cloud.
Drizzle is forecast for much of the day. The forecast total is around 5-10 mm, but local amounts will vary.
Cold on exposed tops: air temperature broadly 2 to 6°C, feeling around -6 to -2°C in the wind. Forecast models disagree markedly on summit wind strength.
Check again nearer the time. Keep windproof and warm layers readily available.
If clothing gets wet, you can cool more quickly. Keep a dry warm layer protected.
The strongest gusts could knock you over on exposed ground. Avoid exposed ridges and edges.
Rain & temperature
The ground is likely to be wet after recent rain.
Forecast confidence
Overall confidence is unavailable: insufficient comparable wind, rain guidance.
0 is the bottom of the scale. Use the hazard details to judge how severe conditions could be.
Cloud-free timing: Around 10% early, improving to around 85% later.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 5.5 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. The strongest gusts could knock you over on exposed ground. Avoid exposed ridges and edges. Rain is forecast during this period.
0/100
Afternoon · 12:00–17:00
PoorSummit winds around 45-55 mph in the early afternoon, easing to 35-45 mph later. Gusts around 65-75 mph are possible on exposed ground. The strongest gusts could knock you over on exposed ground. Avoid exposed ridges and edges. Rain is forecast during this period.
4/100
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaExposed camping is not recommended near 300, 600 and 900 m: gusts may reach about 70 mph. Sustained winds may reach about 50 mph at times. Choose an alternative off the exposed hill. Do not rely on finding shelter after setting out.9/100Poor · 600 mView detailsHide details
Night beginning Tuesday 29 September 2026
Full overnight outlook
Exposed camping is not recommended near 300, 600 and 900 m: gusts may reach about 70 mph. Sustained winds may reach about 50 mph at times. Choose an alternative off the exposed hill. Do not rely on finding shelter after setting out. Open-hillside camping looks very poor overall around 600 m (9/100). Peak gusts range from about 50 mph at 300 m to 70 mph at 900 m. Roughly 10.5 mm is forecast overnight, with rain liable to affect both pitching and packing up. Pitches near 600 and 900 m may spend part of the night in cloud, bringing damp conditions and poor visibility while cloud is present. Condensation risk is high near 900 m. Ventilation will matter. The coldest temperature falls from about 8.3°C at 300 m to 5.5°C at 900 m.
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: 29 Sep, 17:00 BST to 30 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m9/100 · very poor
Wind / gust
33 mph / 51 mph
Typical / low
9.4°C / 8.3°C · much of the night
In cloud
0% of modelled night
Condensation
Moderate
600 m9/100 · very poor
Wind / gust
39 mph / 61 mph
Typical / low
9.2°C / 7.9°C · much of the night
In cloud
40% of modelled night
Condensation
Moderate
900 m0/100 · very poor
Wind / gust
46 mph / 72 mph
Typical / low
6.7°C / 5.5°C · much of the night
In cloud
40% 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.
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Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 70 mph may affect balance on exposed rock.Poor0/100View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Conditions for exposed scrambling look very poor (0/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Pelite (Loch Treig Schist And Quartzite Formation). Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Representative samples along available mapped routes also include Metaquartz-arenite, Pelite and calcsilicate-rock, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 70 mph. Crosswinds can make exposed ridges substantially more serious.
Rock surfaceWet rock likelyPeak gust68 mphRain8.1 mm
Main factorsgusts around 70 mphwet rock likely
Mapped rock across the summit and available routes
PeliteLoch Treig Schist And Quartzite Formation
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery. Summit-point mapping plus representative BGS bedrock samples along available GPX routes. These are not continuous geological surveys; contacts, superficial deposits and the exposed rock on individual holds may differ.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Stob Coire Sgriodain and Chno Dearg
quartzite, sandstone or gritstone, psammite, pelite or semipelite
Geological detail and BGS records
Mapped variation
3 rock types appear across the available route samples
The summit type remains the forecast's cautious rock-response reference. Other mapped types show where conditions may behave differently elsewhere on the mountain.
Summit mapping
PeliteLoch Treig Schist And Quartzite Formation435–1,046 m samplesSeen on Stob Coire Sgriodain and Chno Dearg
Usually hard and grippy when dry and often reasonably positive when damp, although wet lichen and smooth slabs can still be slippery.
BGS record →
Route sample
Metaquartz-areniteReservoir Quartzite MemberAround 643 mSeen on Stob Coire Sgriodain and Chno Dearg
Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully.
BGS record →
Route sample
Pelite and calcsilicate-rockLeven Schist FormationAround 844 mSeen on Stob Coire Sgriodain and Chno Dearg
Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.
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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.
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.
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This is about Chno Dearg on Tuesday 29 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
