Aonach Mòr Weather Forecast – 1,221m, Lochaber

Monday 21 September 2026Confidence: Medium

Overall hill weather23/100Poor

Wind20-35 mph westerly Gusts35-45 mph Feels like0 to 4°C PrecipitationAround 5-10 mm Cloud-free summit estimate5% Cloud base through day600-900 m Freezing levelAbove summit DaylightSunrise 07:01 · Sunset 19:22 · 12.3 hours daylight

The day on the hill

A wet day with extensive summit cloud on Aonach Mòr: summit wind broadly 20-35 mph, with gusts 35-45 mph at times (strong winds). Hill cloud may make navigation difficult, with very poor visibility in wetter spells.

Wind & exposure

Much calmer lower down - generally 10-20 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 western slopes and lift somewhat on the eastern 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 5-10 mm, but local amounts will vary.

Cold on exposed tops: air temperature broadly 4 to 8°C, feeling around 0 to 4°C in the wind. Forecast models differ on summit wind strength: around 21-33 mph at walker height, with gusts 30-47 mph.

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.

Rain & temperature

The ground is likely to be wet after recent rain.

Forecast confidence

Some forecast models bring rain during the main walking period, while others keep it mostly dry.

Sunshine context Model-grid estimate, not summit sunshine

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

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

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

Morning · 08:00–12:00 Poor Summit winds around 15-25 mph. Gusts around 25-35 mph are possible on exposed ground. Rain is forecast during this period.

34/100

Afternoon · 12:00–17:00 Poor More rain is expected. Summit 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. Some forecast models bring rain during the afternoon, while others keep it mostly dry.

12/100

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 50 mph. Sustained winds may reach about 35 mph at times. Choose an alternative off the exposed hill. Do not rely on finding shelter after setting out. 19/100Poor · 600 m View detailsHide details

Night beginning Monday 21 September 2026

Full overnight outlook

Exposed camping is not recommended near 600 and 900 m: gusts may reach about 50 mph. Sustained winds may reach about 35 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 (19/100). Peak gusts range from about 35 mph at 300 m to 50 mph at 900 m. Roughly 5.4 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 10.7°C at 300 m to 9.1°C at 900 m.

Overnight rain5.4 mm Open ground · 600 m27 mph · gusts 42 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 8°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 78%
Moonrise: 18:08 BST
Moonset: 01:11 next morning BST

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

Overnight window: 21 Sep, 17:00 BST to 22 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: 22 mph / 35 mph
Typical / low: 12.0°C / 10.7°C
In cloud: 0% of modelled night
Condensation: High

600 m19/100 · very poor

Wind / gust: 27 mph / 42 mph
Typical / low: 12.0°C / 10.7°C
In cloud: 0% of modelled night
Condensation: High

900 m9/100 · very poor

Wind / gust: 31 mph / 49 mph
Typical / low: 10.4°C / 9.1°C · several hours
In cloud: 100% of modelled night
Condensation: High

Warmth planning: As a broad starting point, consider a 2-season bag with an ISO/EN comfort rating at or below about 8°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

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

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

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 40 mph may affect balance on exposed rock. Poor0/100 View 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 Quartz-diorite (Ben Nevis Complex). Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery. Representative samples along available mapped routes also include Porphyritic granodiorite, Calcareous pelite and 3 other mapped types, 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 gust39 mphRain5.6 mm

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

Mapped rock across the summit and available routes Quartz-diorite Ben Nevis Complex

Origin: Igneous
Rock family: Granite, gneiss or gabbro
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain 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.

Aonach Beag (Nevis Range) and Aonach Mòr

granite, gneiss or gabbro, limestone, sandstone or gritstone, psammite, pelite or semipelite

Aonach Mòr and Aonach Beag (Nevis Range)

granite, gneiss or gabbro, limestone, psammite, pelite or semipelite

Geological detail and BGS records

Mapped variation

6 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 Quartz-diorite Ben Nevis Complex

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Porphyritic granodiorite Ben Nevis Complex (Outer Granite) 658–1,141 m samples Seen on Aonach Mòr and Aonach Beag (Nevis Range)

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Calcareous pelite Ballachulish Limestone Formation Around 1,087 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Usually positive where it is rough and dry, but polished limestone can become very slippery when wet and seepage may linger.

BGS record

Route sample Leucomicrogranodiorite Ben Nevis Complex (Inner Granite) 548–824 m samples Seen on Aonach Beag (Nevis Range) and Aonach Mòr

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Pelite and calcsilicate-rock Leven Schist Formation Around 1,230 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.

BGS record

Route sample Metaquartz-arenite Glen Coe Quartzite Member Around 956 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr

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

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

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Overnight · Aurora, stars & meteorsAfter 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 Aonach Mòr on Monday 21 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

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Tuesday 22 September 2026Confidence: Medium

Overall hill weather13/100Poor

Wind15-35 mph southwesterly Gusts35-45 mph Feels like-2 to 2°C PrecipitationAround 5-10 mm Cloud-free summit estimate5% Cloud base through day600-900 m Freezing levelAbove summit DaylightSunrise 07:04 · Sunset 19:20 · 12.3 hours daylight

The day on the hill

A wet day with extensive summit cloud on Aonach Mòr: summit wind broadly 15-35 mph, with gusts 35-45 mph at times (strong winds). Hill cloud may make navigation difficult, with very poor visibility in wetter spells.

Wind & exposure

Much calmer lower down - generally 0-10 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 5-10 mm, but local amounts will vary.

Cold on exposed tops: air temperature broadly 4 to 8°C, feeling around -2 to 2°C in the wind. Forecast models differ on summit wind strength: around 21-36 mph at walker height, with gusts 30-51 mph.

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.

Rain & temperature

The ground is likely to be wet after recent rain.

Forecast confidence

Summit wind could be roughly 21-36 mph, which changes how difficult exposed walking may feel.

Sunshine context Model-grid estimate, not summit sunshine

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

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

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

Morning · 08:00–12:00 Poor Summit winds around 15-30 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.

0/100

Afternoon · 12:00–17:00 Poor Summit winds around 15-25 mph. Gusts around 25-35 mph are possible on exposed ground. Rain is forecast during this period. Rain is forecast during the afternoon, but models differ considerably on the amount.

26/100

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

Overnight · 17:00–08:00Wild campingBetaAbout 2.4 mm is forecast, with rain liable to affect both pitching and packing up. 64/100Mixed · 600 m View detailsHide details

Night beginning Tuesday 22 September 2026

Full overnight outlook

Open-hillside camping looks reasonable overall around 600 m (64/100). It may be breezy on open ground, with gusts near 25 mph. Peak gusts range from about 15 mph at 300 m to 25 mph at 900 m. Around 2.4 mm is forecast, 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 6.3°C at 300 m to 4.4°C at 900 m.

Overnight rain2.4 mm Open ground · 600 m11 mph · gusts 20 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 86%
Moonrise: 18:19 BST
Moonset: 02:37 next morning BST

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 m64/100 · reasonable

Wind / gust: 10 mph / 16 mph
Typical / low: 8.6°C / 6.3°C · much of the night
In cloud: 0% of modelled night
Condensation: High

600 m64/100 · reasonable

Wind / gust: 11 mph / 20 mph
Typical / low: 8.6°C / 6.3°C · much of the night
In cloud: 0% of modelled night
Condensation: High

900 m54/100 · mixed

Wind / gust: 13 mph / 23 mph
Typical / low: 6.8°C / 4.4°C · a brief spell
In cloud: 80% of modelled night
Condensation: High

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

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

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

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 40 mph may affect balance on exposed rock. Poor0/100 View 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 Quartz-diorite (Ben Nevis Complex). Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery. Representative samples along available mapped routes also include Porphyritic granodiorite, Calcareous pelite and 3 other mapped types, 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 mphRain9.1 mm

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

Mapped rock across the summit and available routes Quartz-diorite Ben Nevis Complex

Origin: Igneous
Rock family: Granite, gneiss or gabbro
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain 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.

Aonach Beag (Nevis Range) and Aonach Mòr

granite, gneiss or gabbro, limestone, sandstone or gritstone, psammite, pelite or semipelite

Aonach Mòr and Aonach Beag (Nevis Range)

granite, gneiss or gabbro, limestone, psammite, pelite or semipelite

Geological detail and BGS records

Mapped variation

6 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 Quartz-diorite Ben Nevis Complex

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Porphyritic granodiorite Ben Nevis Complex (Outer Granite) 658–1,141 m samples Seen on Aonach Mòr and Aonach Beag (Nevis Range)

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Calcareous pelite Ballachulish Limestone Formation Around 1,087 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Usually positive where it is rough and dry, but polished limestone can become very slippery when wet and seepage may linger.

BGS record

Route sample Leucomicrogranodiorite Ben Nevis Complex (Inner Granite) 548–824 m samples Seen on Aonach Beag (Nevis Range) and Aonach Mòr

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Pelite and calcsilicate-rock Leven Schist Formation Around 1,230 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.

BGS record

Route sample Metaquartz-arenite Glen Coe Quartzite Member Around 956 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr

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

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

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

Overnight · Aurora, stars & meteorsAfter darkBetaNight-sky guidance is unavailable for this night. View forecastClose forecast

After dark: aurora and stargazing

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

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 Aonach Mòr on Tuesday 22 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Wednesday 23 September 2026Confidence: Medium

Overall hill weather67/100Mixed

Wind10-20 mph northwesterly Gusts15-25 mph Feels like-4 to 0°C PrecipitationUp to around 2 mm Cloud-free summit estimate35% Cloud base through day600-1,800 m Freezing levelAbove summit DaylightSunrise 07:06 · Sunset 19:17 · 12.2 hours daylight

The day on the hill

Frequent summit cloud on Aonach Mòr: summit wind broadly 10-20 mph, with gusts 15-25 mph at times (a moderate breeze).

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. The top is likely to drift in and out of cloud, with the best chance of a view from late afternoon into the evening.

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 0 to 4°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 0% early, improving to around 70% later.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 6.2 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.

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.

Early: Less than 1 hour
Midday: 1.4 h
Later: 3 h

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

Morning · 08:00–12:00 Mixed Summit winds around 10-20 mph. Gusts around 15-25 mph are possible on exposed ground. Rain is forecast during this period.

62/100

Afternoon · 12:00–17:00 Good Summit winds around 10-20 mph. Gusts around 15-25 mph are possible on exposed ground. Summit cloud is more persistent early in this period, with better prospects later.

72/100

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 m View 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 30 mph. 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. Little overnight rain is forecast. The coldest temperature falls from about 5.9°C at 300 m to 4.3°C at 900 m.

Overnight rain0.0 mm Open ground · 600 m10 mph · gusts 24 mph Morning pack-upNo wet signal Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 92%
Moonrise: 18:26 BST
Moonset: 04:02 next morning BST

Views of the Moon may come and go through cloud breaks. 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 / 21 mph
Typical / low: 6.4°C / 5.9°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m85/100 · promising

Wind / gust: 10 mph / 24 mph
Typical / low: 6.4°C / 5.9°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

900 m59/100 · mixed

Wind / gust: 11 mph / 28 mph
Typical / low: 4.6°C / 4.3°C · much of the night
In cloud: 7% of modelled night
Condensation: Low

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

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

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

Daytime · exposed rockClimbing & scramblingBetaRock may be damp or still drying. Poor43/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look mixed (43/100). Recent rain may leave seepage and damp rock, especially on shaded sections. The mapped summit rock is Quartz-diorite (Ben Nevis Complex). Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery. Representative samples along available mapped routes also include Porphyritic granodiorite, Calcareous pelite and 3 other mapped types, so rock character and wet-weather behaviour may change across the mountain. Cloud may also make route-finding and retreat harder.

Rock surfaceDry overhead; seepage uncertainPeak gust21 mphRain0.2 mm

Main factorsdamp or incompletely dried rock possiblemuch of the route may be in cloud

Mapped rock across the summit and available routes Quartz-diorite Ben Nevis Complex

Origin: Igneous
Rock family: Granite, gneiss or gabbro
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain 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.

Aonach Beag (Nevis Range) and Aonach Mòr

granite, gneiss or gabbro, limestone, sandstone or gritstone, psammite, pelite or semipelite

Aonach Mòr and Aonach Beag (Nevis Range)

granite, gneiss or gabbro, limestone, psammite, pelite or semipelite

Geological detail and BGS records

Mapped variation

6 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 Quartz-diorite Ben Nevis Complex

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Porphyritic granodiorite Ben Nevis Complex (Outer Granite) 658–1,141 m samples Seen on Aonach Mòr and Aonach Beag (Nevis Range)

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Calcareous pelite Ballachulish Limestone Formation Around 1,087 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Usually positive where it is rough and dry, but polished limestone can become very slippery when wet and seepage may linger.

BGS record

Route sample Leucomicrogranodiorite Ben Nevis Complex (Inner Granite) 548–824 m samples Seen on Aonach Beag (Nevis Range) and Aonach Mòr

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Pelite and calcsilicate-rock Leven Schist Formation Around 1,230 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.

BGS record

Route sample Metaquartz-arenite Glen Coe Quartzite Member Around 956 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr

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

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

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

Overnight · Aurora, stars & meteorsAfter darkBetaNight-sky guidance is unavailable for this night. View forecastClose forecast

After dark: aurora and stargazing

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

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 Aonach Mòr on Wednesday 23 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Thursday 24 September 2026Confidence: Low

Overall hill weather36/100Poor

Wind30-50 mph southwesterly Gusts55-65 mph Feels like-8 to -4°C PrecipitationUp to around 2 mm Cloud-free summit estimate85% Cloud base through day1,400-2,200 m Freezing level1,100-1,400 m DaylightSunrise 07:08 · Sunset 19:14 · 12.1 hours daylight

The day on the hill

Strong gusts on Aonach Mòr: summit wind broadly 30-50 mph, with gusts 55-65 mph at times (gale-force mean winds at times).

Wind & exposure

Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops. Drizzle is forecast at times.

The forecast total is up to around 2 mm, but local amounts will vary. Cold on exposed tops: air temperature broadly -2 to 2°C, feeling around -8 to -4°C in the wind.

Summit wind strength is uncertain: around 27-58 mph at walker height, with gusts 38-81 mph. 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.

Forecast confidence

Summit wind could be roughly 27-58 mph, which changes how difficult exposed walking may feel.

Cloud-free timing: Around 90% early, falling to around 55% later.

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.

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

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

Morning · 08:00–12:00 Poor Summit winds around 15-25 mph early in the morning, strengthening to 30-40 mph later. Gusts around 40-50 mph are possible on exposed ground. Gusts may knock you off balance on exposed ground, even between spells of lighter wind. Rain is possible during the morning, but forecast models disagree on whether it will fall.

45/100

Afternoon · 12:00–17:00 Poor Winds 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. Rain is forecast during the afternoon, but models differ considerably on the amount.

27/100

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 65 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 m View detailsHide details

Night beginning Thursday 24 September 2026

Full overnight outlook

Exposed camping is not recommended near 300, 600 and 900 m: gusts may reach about 65 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 65 mph at 900 m. Roughly 13 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 8.3°C at 300 m to 5.7°C at 900 m.

Overnight rain13.0 mm Open ground · 600 m30 mph · gusts 55 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 97%
Moonrise: 18:32 BST
Moonset: 05:27 next morning BST

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 m19/100 · very poor

Wind / gust: 25 mph / 45 mph
Typical / low: 10.3°C / 8.3°C · several hours
In cloud: 0% of modelled night
Condensation: Moderate

600 m9/100 · very poor

Wind / gust: 30 mph / 55 mph
Typical / low: 9.9°C / 7.9°C · several hours
In cloud: 80% of modelled night
Condensation: High

900 m0/100 · very poor

Wind / gust: 35 mph / 65 mph
Typical / low: 8.0°C / 5.7°C · much of the night
In cloud: 87% of modelled night
Condensation: High

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

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

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

Daytime · exposed rockClimbing & scramblingBetaSub-zero temperatures and moisture may leave icy patches on exposed rock. Wet rock is likely. Gusts near 60 mph may affect balance on exposed rock. Poor0/100 View 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 Quartz-diorite (Ben Nevis Complex). Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery. Representative samples along available mapped routes also include Porphyritic granodiorite, Calcareous pelite and 3 other mapped types, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 60 mph. Crosswinds can make exposed ridges substantially more serious. Sub-zero temperatures and moisture may leave icy patches on exposed rock. Treat the route as a winter mountaineering proposition if deposits are present.

Rock surfaceWet rock likelyPeak gust58 mphRain0.6 mm

Main factorsgusts around 60 mphwet rock likelySub-zero temperatures and moisture may leave icy patches on exposed rock

Mapped rock across the summit and available routes Quartz-diorite Ben Nevis Complex

Origin: Igneous
Rock family: Granite, gneiss or gabbro
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain 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.

Aonach Beag (Nevis Range) and Aonach Mòr

granite, gneiss or gabbro, limestone, sandstone or gritstone, psammite, pelite or semipelite

Aonach Mòr and Aonach Beag (Nevis Range)

granite, gneiss or gabbro, limestone, psammite, pelite or semipelite

Geological detail and BGS records

Mapped variation

6 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 Quartz-diorite Ben Nevis Complex

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Porphyritic granodiorite Ben Nevis Complex (Outer Granite) 658–1,141 m samples Seen on Aonach Mòr and Aonach Beag (Nevis Range)

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Calcareous pelite Ballachulish Limestone Formation Around 1,087 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Usually positive where it is rough and dry, but polished limestone can become very slippery when wet and seepage may linger.

BGS record

Route sample Leucomicrogranodiorite Ben Nevis Complex (Inner Granite) 548–824 m samples Seen on Aonach Beag (Nevis Range) and Aonach Mòr

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Pelite and calcsilicate-rock Leven Schist Formation Around 1,230 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.

BGS record

Route sample Metaquartz-arenite Glen Coe Quartzite Member Around 956 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr

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

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

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

Overnight · Aurora, stars & meteorsAfter darkBetaNight-sky guidance is unavailable for this night. View forecastClose forecast

After dark: aurora and stargazing

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

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 Aonach Mòr on Thursday 24 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Friday 25 September 2026Confidence: Medium

Overall hill weather32/100Poor

Wind20-30 mph southwesterly Gusts30-40 mph Feels like-6 to -2°C PrecipitationAround 2-5 mm Cloud-free summit estimate10% Cloud base through day500-1,000 m Freezing levelAbove summit DaylightSunrise 07:10 · Sunset 19:11 · 12.0 hours daylight

The day on the hill

A wet day with extensive summit cloud on Aonach Mòr: summit wind broadly 20-30 mph, with gusts 30-40 mph at times (a fresh breeze).

Wind & exposure

Much calmer lower down - generally 0-10 mph in the valley, rising towards the tops.

Cloud & views

Cloud base around 500–800 m through the morning, lifting to 700–1000 m by late afternoon. 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. 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 0 to 4°C, feeling around -6 to -2°C in the wind. Forecast models differ on summit wind strength: around 11-30 mph at walker height, with gusts 15-42 mph.

Keep windproof and warm layers readily available. If clothing gets wet, you can cool more quickly.

Keep a dry warm layer protected.

Forecast confidence

Forecast models differ on whether meaningful rain reaches the hills during the main walking period.

Cloud-free timing: Around 0% early, improving to around 30% 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.

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.

Early: 2 h
Midday: 4 h
Later: 3 h

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

Morning · 08:00–12:00 Poor Summit winds around 15-25 mph. Gusts around 25-35 mph are possible on exposed ground. Rain is forecast during this period.

37/100

Afternoon · 12:00–17:00 Poor Summit winds around 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Rain is forecast during this period. Rain is possible during the afternoon, but forecast models disagree on whether it will fall.

28/100

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 35 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 m View 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 35 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 1 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 900 m. Ventilation will matter. The coldest temperature falls from about 7.5°C at 300 m to 5.2°C at 900 m.

Overnight rain1.0 mm Open ground · 600 m24 mph · gusts 39 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Near-full moon

Illuminated disc: 99%
Moonrise: 18:37 BST
Moonset: 06:53 next morning BST

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 / 32 mph
Typical / low: 7.7°C / 7.5°C · much of the night
In cloud: 0% of modelled night
Condensation: Moderate

600 m39/100 · poor

Wind / gust: 24 mph / 39 mph
Typical / low: 7.4°C / 7.3°C · much of the night
In cloud: 60% of modelled night
Condensation: Moderate

900 m19/100 · very poor

Wind / gust: 28 mph / 46 mph
Typical / low: 5.4°C / 5.2°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.

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

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

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 35 mph may affect balance on exposed rock. Poor0/100 View 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 Quartz-diorite (Ben Nevis Complex). Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery. Representative samples along available mapped routes also include Porphyritic granodiorite, Calcareous pelite and 3 other mapped types, 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 gust35 mphRain2.7 mm

Main factorsgusts around 35 mphwet rock likelymuch of the route may be in cloud

Mapped rock across the summit and available routes Quartz-diorite Ben Nevis Complex

Origin: Igneous
Rock family: Granite, gneiss or gabbro
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain 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.

Aonach Beag (Nevis Range) and Aonach Mòr

granite, gneiss or gabbro, limestone, sandstone or gritstone, psammite, pelite or semipelite

Aonach Mòr and Aonach Beag (Nevis Range)

granite, gneiss or gabbro, limestone, psammite, pelite or semipelite

Geological detail and BGS records

Mapped variation

6 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 Quartz-diorite Ben Nevis Complex

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Porphyritic granodiorite Ben Nevis Complex (Outer Granite) 658–1,141 m samples Seen on Aonach Mòr and Aonach Beag (Nevis Range)

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Calcareous pelite Ballachulish Limestone Formation Around 1,087 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Usually positive where it is rough and dry, but polished limestone can become very slippery when wet and seepage may linger.

BGS record

Route sample Leucomicrogranodiorite Ben Nevis Complex (Inner Granite) 548–824 m samples Seen on Aonach Beag (Nevis Range) and Aonach Mòr

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Pelite and calcsilicate-rock Leven Schist Formation Around 1,230 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.

BGS record

Route sample Metaquartz-arenite Glen Coe Quartzite Member Around 956 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr

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

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

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

Overnight · Aurora, stars & meteorsAfter darkBetaNight-sky guidance is unavailable for this night. View forecastClose forecast

After dark: aurora and stargazing

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

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 Aonach Mòr on Friday 25 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Saturday 26 September 2026Confidence: Medium

Overall hill weather6/100Poor

Wind30-40 mph southwesterly Gusts45-55 mph Feels like-6 to -2°C PrecipitationAround 10-20 mm Cloud-free summit estimate0% Cloud base through day500-1,000 m Freezing levelAbove summit DaylightSunrise 07:12 · Sunset 19:09 · 11.9 hours daylight

The day on the hill

Strong gusts and frequent summit cloud on Aonach Mòr: summit wind broadly 30-40 mph, with gusts 45-55 mph at times (strong winds). Visibility may drop briefly in showers.

Wind & exposure

Much calmer lower down - generally 5-15 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 around 500–800 m in the morning, then around 700–1000 m around midday and 500–800 m by late afternoon. 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. 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 10-20 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 17-43 mph at walker height, with gusts 24-60 mph.

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.

Forecast models differ on whether meaningful rain reaches the hills during the afternoon and evening.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 10.7 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.

Early: 1.8 h
Midday: 4 h
Later: 3 h

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

Morning · 08:00–12:00 Poor Summit winds around 25-35 mph. Gusts around 40-50 mph are possible on exposed ground. Gusts may knock you off balance on exposed ground, even between spells of lighter wind. Rain is forecast during this period.

15/100

Afternoon · 12:00–17:00 Severe hill conditions More rain is expected. Summit winds around 30-40 mph. 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. Rain is forecast during this period. Rain is possible during the afternoon, but forecast models disagree on whether it will fall.

0/100

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 50 mph. Sustained winds may reach about 35 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 m View detailsHide details

Night beginning Saturday 26 September 2026

Full overnight outlook

Exposed camping is not recommended near 900 m: gusts may reach about 50 mph. Sustained winds may reach about 35 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 35 mph at 300 m to 50 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 600 and 900 m. Ventilation will matter. The coldest temperature falls from about 9.9°C at 300 m to 7.6°C at 900 m.

Overnight rain10.5 mm Open ground · 600 m24 mph · gusts 41 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 6°C or lower

Moon overnight

Near-full moon

Illuminated disc: 100%
Moonrise: 18:42 BST
Moonset: Outside this window

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 m49/100 · mixed

Wind / gust: 20 mph / 34 mph
Typical / low: 10.2°C / 9.9°C · several hours
In cloud: 0% of modelled night
Condensation: Moderate

600 m39/100 · poor

Wind / gust: 24 mph / 41 mph
Typical / low: 9.8°C / 9.5°C · much of the night
In cloud: 100% of modelled night
Condensation: High

900 m19/100 · very poor

Wind / gust: 29 mph / 48 mph
Typical / low: 8.0°C / 7.6°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.

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

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

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 50 mph may affect balance on exposed rock. Poor0/100 View 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 Quartz-diorite (Ben Nevis Complex). Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery. Representative samples along available mapped routes also include Porphyritic granodiorite, Calcareous pelite and 3 other mapped types, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 50 mph. Crosswinds can make exposed ridges substantially more serious. Cloud may also make route-finding and retreat harder.

Rock surfaceWet rock likelyPeak gust49 mphRain12.2 mm

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

Mapped rock across the summit and available routes Quartz-diorite Ben Nevis Complex

Origin: Igneous
Rock family: Granite, gneiss or gabbro
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain 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.

Aonach Beag (Nevis Range) and Aonach Mòr

granite, gneiss or gabbro, limestone, sandstone or gritstone, psammite, pelite or semipelite

Aonach Mòr and Aonach Beag (Nevis Range)

granite, gneiss or gabbro, limestone, psammite, pelite or semipelite

Geological detail and BGS records

Mapped variation

6 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 Quartz-diorite Ben Nevis Complex

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Porphyritic granodiorite Ben Nevis Complex (Outer Granite) 658–1,141 m samples Seen on Aonach Mòr and Aonach Beag (Nevis Range)

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Calcareous pelite Ballachulish Limestone Formation Around 1,087 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Usually positive where it is rough and dry, but polished limestone can become very slippery when wet and seepage may linger.

BGS record

Route sample Leucomicrogranodiorite Ben Nevis Complex (Inner Granite) 548–824 m samples Seen on Aonach Beag (Nevis Range) and Aonach Mòr

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Pelite and calcsilicate-rock Leven Schist Formation Around 1,230 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.

BGS record

Route sample Metaquartz-arenite Glen Coe Quartzite Member Around 956 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr

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

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

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

Overnight · Aurora, stars & meteorsAfter darkBetaNight-sky guidance is unavailable for this night. View forecastClose forecast

After dark: aurora and stargazing

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

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 Aonach Mòr on Saturday 26 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Sunday 27 September 2026Confidence: Unavailable

Overall hill weather35/100Poor

Wind20-35 mph southerly Gusts35-45 mph Feels like-2 to 2°C PrecipitationLittle or none Cloud-free summit estimate45% Cloud base through day700-2,300 m Freezing levelAbove summit DaylightSunrise 07:14 · Sunset 19:06 · 11.9 hours daylight

The day on the hill

On Aonach Mòr: summit wind broadly 20-35 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, lifting to 900–1200 m around midday and 2000–2300 m by late afternoon. The top is likely to drift in and out of cloud, with the best chance of a view from late afternoon into the evening.

Cloud-height uncertainty could put the summit in or out of cloud. Clear spells may be difficult to time.

Cloud may hang lower on southern slopes and lift somewhat on the northern 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 4 to 8°C, feeling around -2 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.

Buffeting may affect balance on exposed ground, particularly near ridges and edges. Overall confidence is unavailable: insufficient comparable wind, rain guidance.

Cloud-free timing: Around 5% early, improving to around 95% later.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 7.4 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.

Early: 0 h
Midday: 3.3 h
Later: 3 h

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

Morning · 08:00–12:00 Poor Summit 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. Some forecast models bring rain during the morning, while others keep it mostly dry.

27/100

Afternoon · 12:00–17:00 Poor Summit 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. Summit cloud is more persistent early in this period, with better prospects later. Some forecast models bring rain during the afternoon, while others keep it mostly dry.

43/100

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 m View detailsHide details

Night beginning Sunday 27 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 2.6 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.

Overnight rain2.6 mm Open ground · 600 m23 mph · gusts 38 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Waning gibbous moon

Illuminated disc: 98%
Moonrise: 18:48 BST
Moonset: Outside this window

Extensive cloud may limit moonlight. 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 m59/100 · mixed

Wind / gust: 20 mph / 31 mph
Typical / low: 10.9°C / 5.5°C · several hours
In cloud: 0% of modelled night
Condensation: Low

600 m39/100 · poor

Wind / gust: 23 mph / 38 mph
Typical / low: 9.1°C / 5.5°C · much of the night
In cloud: 0% of modelled night
Condensation: Moderate

900 m19/100 · very poor

Wind / gust: 28 mph / 44 mph
Typical / low: 8.0°C / 4.3°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 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

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

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

Daytime · exposed rockClimbing & scramblingBetaRock may be damp or still drying. Gusts near 40 mph may affect balance on exposed rock. Poor27/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look poor (27/100). Recent rain may leave seepage and damp rock, especially on shaded sections. The mapped summit rock is Quartz-diorite (Ben Nevis Complex). Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery. Representative samples along available mapped routes also include Porphyritic granodiorite, Calcareous pelite and 3 other mapped types, 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 surfaceDry overhead; seepage uncertainPeak gust40 mphRain0.0 mm

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

Mapped rock across the summit and available routes Quartz-diorite Ben Nevis Complex

Origin: Igneous
Rock family: Granite, gneiss or gabbro
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain 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.

Aonach Beag (Nevis Range) and Aonach Mòr

granite, gneiss or gabbro, limestone, sandstone or gritstone, psammite, pelite or semipelite

Aonach Mòr and Aonach Beag (Nevis Range)

granite, gneiss or gabbro, limestone, psammite, pelite or semipelite

Geological detail and BGS records

Mapped variation

6 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 Quartz-diorite Ben Nevis Complex

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Porphyritic granodiorite Ben Nevis Complex (Outer Granite) 658–1,141 m samples Seen on Aonach Mòr and Aonach Beag (Nevis Range)

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Calcareous pelite Ballachulish Limestone Formation Around 1,087 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Usually positive where it is rough and dry, but polished limestone can become very slippery when wet and seepage may linger.

BGS record

Route sample Leucomicrogranodiorite Ben Nevis Complex (Inner Granite) 548–824 m samples Seen on Aonach Beag (Nevis Range) and Aonach Mòr

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Pelite and calcsilicate-rock Leven Schist Formation Around 1,230 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.

BGS record

Route sample Metaquartz-arenite Glen Coe Quartzite Member Around 956 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr

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

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

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

Overnight · Aurora, stars & meteorsAfter darkBetaNight-sky guidance is unavailable for this night. View forecastClose forecast

After dark: aurora and stargazing

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

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 Aonach Mòr on Sunday 27 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Monday 28 September 2026Confidence: Unavailable

Overall hill weather22/100Poor

Wind20-30 mph southwesterly Gusts30-40 mph Feels like-6 to -2°C PrecipitationAround 5-10 mm Cloud-free summit estimate5% Cloud base through day700-1,000 m Freezing levelAbove summit DaylightSunrise 07:16 · Sunset 19:03 · 11.8 hours daylight

The day on the hill

A wet day with extensive summit cloud on Aonach Mòr: summit wind broadly 20-30 mph, with gusts 30-40 mph at times (strong winds). Visibility may drop briefly in showers.

Wind & exposure

Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops.

Cloud & views

Cloud base mostly around 700–1000 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. 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 0 to 4°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.

Buffeting may affect balance on exposed ground, particularly near 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.

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.

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.

Early: Less than 1 hour
Midday: 3.2 h
Later: 2.8 h

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

Morning · 08:00–12:00 Poor Summit 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.

22/100

Afternoon · 12:00–17:00 Poor Summit 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.

23/100

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 40 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 m View detailsHide details

Night beginning Monday 28 September 2026

Full overnight outlook

Exposed camping is not recommended near 900 m: gusts may reach about 40 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 40 mph at 900 m. Around 1.9 mm is forecast, 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. It may be only a few degrees above freezing at the coldest point of the night near 900 m. Around 600 m the low near 5°C is forecast for a brief spell.

Overnight rain1.9 mm Open ground · 600 m20 mph · gusts 35 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Waning gibbous moon

Illuminated disc: 94%
Moonrise: 18:56 BST
Moonset: Outside this window

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 m59/100 · mixed

Wind / gust: 16 mph / 29 mph
Typical / low: 5.3°C / 5.0°C · a brief spell
In cloud: 0% of modelled night
Condensation: High

600 m39/100 · poor

Wind / gust: 20 mph / 35 mph
Typical / low: 5.3°C / 5.0°C · a brief spell
In cloud: 0% of modelled night
Condensation: High

900 m19/100 · very poor

Wind / gust: 23 mph / 42 mph
Typical / low: 4.2°C / 3.9°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 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

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

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

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 35 mph may affect balance on exposed rock. Poor28/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look poor (28/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Quartz-diorite (Ben Nevis Complex). Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery. Representative samples along available mapped routes also include Porphyritic granodiorite, Calcareous pelite and 3 other mapped types, 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 mphRain7.6 mm

Main factorsgusts around 35 mphwet rock likelymuch of the route may be in cloud

Mapped rock across the summit and available routes Quartz-diorite Ben Nevis Complex

Origin: Igneous
Rock family: Granite, gneiss or gabbro
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain 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.

Aonach Beag (Nevis Range) and Aonach Mòr

granite, gneiss or gabbro, limestone, sandstone or gritstone, psammite, pelite or semipelite

Aonach Mòr and Aonach Beag (Nevis Range)

granite, gneiss or gabbro, limestone, psammite, pelite or semipelite

Geological detail and BGS records

Mapped variation

6 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 Quartz-diorite Ben Nevis Complex

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Porphyritic granodiorite Ben Nevis Complex (Outer Granite) 658–1,141 m samples Seen on Aonach Mòr and Aonach Beag (Nevis Range)

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Calcareous pelite Ballachulish Limestone Formation Around 1,087 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Usually positive where it is rough and dry, but polished limestone can become very slippery when wet and seepage may linger.

BGS record

Route sample Leucomicrogranodiorite Ben Nevis Complex (Inner Granite) 548–824 m samples Seen on Aonach Beag (Nevis Range) and Aonach Mòr

Generally grippy when dry and often still positive when damp, but wet slabs, lichen, polish and drainage lines can remain slippery.

BGS record

Route sample Pelite and calcsilicate-rock Leven Schist Formation Around 1,230 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr, Aonach Mòr and Aonach Beag (Nevis Range)

Dry quartz-rich bands can be grippy, while mica-rich or foliated sections, lichen and vegetation may become slippery when wet.

BGS record

Route sample Metaquartz-arenite Glen Coe Quartzite Member Around 956 m Seen on Aonach Beag (Nevis Range) and Aonach Mòr

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

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

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

Overnight · Aurora, stars & meteorsAfter darkBetaNight-sky guidance is unavailable for this night. View forecastClose forecast

After dark: aurora and stargazing

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

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 Aonach Mòr on Monday 28 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Aonach Mòr weather forecast.

Choose your hill day.

The day on the hill

Wind & exposure

Cloud & views

Rain & temperature

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Aonach Beag (Nevis Range) and Aonach Mòr

Aonach Mòr and Aonach Beag (Nevis Range)

6 rock types appear across the available route samples

After dark: aurora and stargazing

The day on the hill

Wind & exposure

Cloud & views

Rain & temperature

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Aonach Beag (Nevis Range) and Aonach Mòr

Aonach Mòr and Aonach Beag (Nevis Range)

6 rock types appear across the available route samples

After dark: aurora and stargazing

The day on the hill

Cloud & views

Rain & temperature

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Aonach Beag (Nevis Range) and Aonach Mòr

Aonach Mòr and Aonach Beag (Nevis Range)

6 rock types appear across the available route samples

After dark: aurora and stargazing

The day on the hill

Wind & exposure

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Aonach Beag (Nevis Range) and Aonach Mòr

Aonach Mòr and Aonach Beag (Nevis Range)

6 rock types appear across the available route samples

After dark: aurora and stargazing

The day on the hill

Wind & exposure

Cloud & views

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Aonach Beag (Nevis Range) and Aonach Mòr

Aonach Mòr and Aonach Beag (Nevis Range)

6 rock types appear across the available route samples

After dark: aurora and stargazing

The day on the hill

Wind & exposure

Cloud & views

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Aonach Beag (Nevis Range) and Aonach Mòr

Aonach Mòr and Aonach Beag (Nevis Range)

6 rock types appear across the available route samples