Càrn Mairg Weather Forecast – 1,042m, Perthshire Highlands

Sunday 20 September 2026Confidence: Medium

Overall hill weather34/100Poor

Wind25-50 mph westerly Gusts55-65 mph Feels like-6 to -2°C PrecipitationLittle or none Cloud-free summit estimate60% Cloud base through day500-1,800 m Freezing levelAbove summit DaylightSunrise 06:56 · Sunset 19:22 · 12.4 hours daylight

The day on the hill

Strong gusts on Càrn Mairg: summit wind broadly 25-50 mph, with gusts 55-65 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.

Cloud & views

Cloud base around 500–800 m in the morning, then around 1500–1800 m around midday and 1300–1600 m by late afternoon. The top is likely to drift in and out of cloud, with the best chance of a view from around midday 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 western slopes and lift somewhat on the eastern 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

Little or no rain is forecast. 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 41-48 mph at walker height, with gusts 58-67 mph.

Forecast confidence

Cloud height remains uncertain, especially where it is close to summit level. Keep windproof and warm layers readily available.

The strongest gusts could knock you over on exposed ground. Avoid exposed ridges and edges.

Cloud-height uncertainty could put the summit in or out of cloud, even where forecasts agree on the wider cloud cover.

Cloud-free timing: Cloudy early, clearing later.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 9 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 1.9 h
Midday: 3.6 h
Later: 1.4 h

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

Morning · 08:00–12:00 Poor 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.

14/100

Afternoon · 12:00–17:00 Mixed Winds ease compared with the morning. Summit winds around 20-35 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. Summit cloud is more persistent early in this period, with better prospects later.

55/100

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

Overnight · 17:00–08:00Wild campingBetaGusts near 35 mph make meaningful shelter important. 59/100Mixed · 600 m View detailsHide details

Night beginning Sunday 20 September 2026

Full overnight outlook

Open-hillside camping looks mixed overall around 600 m (59/100). A lower pitch near 300 m looks more comfortable. Conditions are less suitable by 900 m. Open-ground gusts may reach about 35 mph. Seek meaningful shelter. Peak gusts range from about 25 mph at 300 m to 35 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. The coldest temperature falls from about 6.9°C at 300 m to 5.2°C at 900 m.

Overnight rain0.1 mm Open ground · 600 m17 mph · gusts 31 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 70%
Moonrise: 17:46 BST
Moonset: 23:46 BST

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

Overnight window: 20 Sep, 17:00 BST to 21 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: 14 mph / 26 mph
Typical / low: 7.8°C / 6.9°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m59/100 · mixed

Wind / gust: 17 mph / 31 mph
Typical / low: 7.8°C / 6.9°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

900 m39/100 · poor

Wind / gust: 20 mph / 35 mph
Typical / low: 6.1°C / 5.2°C · much of the night
In cloud: 33% of modelled night
Condensation: Moderate

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 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 & scramblingBetaRock may be damp or still drying. Gusts near 55 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). Recent rain may leave seepage and damp rock, especially on shaded sections. The mapped summit rock is Gritty psammite (Carn Mairg 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 Calcareous pelite, Graphitic pelite, 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 surfaceDry overhead; seepage uncertainPeak gust55 mphRain0.0 mm

Main factorsgusts around 55 mphdamp or incompletely dried rock possible

Mapped rock across the summit and available routes Gritty psammite Carn Mairg Quartzite Formation

Origin: Metamorphic
Rock family: Quartzite
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

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.

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

quartzite, 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 Gritty psammite Carn Mairg Quartzite Formation 305–1,038 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Calcareous pelite Ben Lawers Schist Formation 513–828 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Graphitic pelite Ben Eagach Schist Formation Around 410 m Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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

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 Càrn Mairg on Sunday 20 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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Monday 21 September 2026Confidence: Medium

Overall hill weather49/100Poor

Wind15-30 mph westerly Gusts35-45 mph Feels like0 to 4°C PrecipitationLittle or none Cloud-free summit estimate10% Cloud base through day600-900 m Freezing levelAbove summit DaylightSunrise 06:58 · Sunset 19:19 · 12.3 hours daylight

The day on the hill

Frequent summit cloud on Càrn Mairg: summit wind broadly 15-30 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 mostly around 600–900 m through daylight. 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 western slopes and lift somewhat on the eastern side, but local terrain can differ. Any sunshine may be confined to lower ground or breaks away from the summit.

Rain & temperature

Little or no rain is forecast. Forecast models differ on summit wind strength: around 22-34 mph at walker height, with gusts 31-48 mph.

Forecast confidence

Cloud height remains uncertain, especially where it is close to summit level. Exposed tops may feel chilly in the wind.

A windproof layer will help, with an extra warm layer for stops. Buffeting may affect balance on exposed ground, particularly near ridges and edges.

Cloud-height uncertainty could put the summit in or out of cloud, even where forecasts agree on the wider cloud cover.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates Less than 1 hour 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: Less than 1 hour
Later: 0 h

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

Morning · 08:00–12:00 Mixed Summit winds around 10-20 mph. Gusts around 20-30 mph are possible on exposed ground.

56/100

Afternoon · 12:00–17:00 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.

42/100

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 Monday 21 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. 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. Condensation risk is high near 900 m. Ventilation will matter. The coldest temperature falls from about 11°C at 300 m to 9.3°C at 900 m.

Overnight rain0.0 mm Open ground · 600 m24 mph · gusts 38 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 8°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 78%
Moonrise: 18:03 BST
Moonset: 01:09 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: 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 m59/100 · mixed

Wind / gust: 20 mph / 31 mph
Typical / low: 11.9°C / 11.0°C
In cloud: 0% of modelled night
Condensation: Moderate

600 m39/100 · poor

Wind / gust: 24 mph / 38 mph
Typical / low: 11.9°C / 11.0°C
In cloud: 0% of modelled night
Condensation: Moderate

900 m19/100 · very poor

Wind / gust: 28 mph / 44 mph
Typical / low: 10.3°C / 9.3°C · several hours
In cloud: 93% 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 & scramblingBetaRock may be damp or still drying. Gusts near 40 mph may affect balance on exposed rock. Poor31/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look poor (31/100). Some rock may still be damp or drying, especially on polished slabs and vegetated sections. The mapped summit rock is Gritty psammite (Carn Mairg 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 Calcareous pelite, Graphitic pelite, 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 surfaceDamp or dryingPeak gust38 mphRain0.1 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 Gritty psammite Carn Mairg Quartzite Formation

Origin: Metamorphic
Rock family: Quartzite
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

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.

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

quartzite, 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 Gritty psammite Carn Mairg Quartzite Formation 305–1,038 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Calcareous pelite Ben Lawers Schist Formation 513–828 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Graphitic pelite Ben Eagach Schist Formation Around 410 m Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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

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 Càrn Mairg on Monday 21 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

Tuesday 22 September 2026Confidence: Medium

Overall hill weather44/100Poor

Wind15-35 mph westerly Gusts35-45 mph Feels like2 to 6°C PrecipitationUp to around 2 mm Cloud-free summit estimate25% Cloud base through day600-1,100 m Freezing levelAbove summit DaylightSunrise 07:00 · Sunset 19:16 · 12.3 hours daylight

The day on the hill

Frequent summit cloud on Càrn Mairg: summit wind broadly 15-35 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 800–1100 m in the morning, then around 600–900 m around midday and 800–1100 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 western slopes and lift somewhat on the eastern side, but local terrain can differ. Any sunshine may be confined to lower ground or breaks away from the summit.

Drizzle is forecast at times. The forecast total is up to around 2 mm, but local amounts will vary.

Forecast models differ on summit wind strength: around 20-32 mph at walker height, with gusts 28-45 mph.

Forecast confidence

Cloud height remains uncertain, especially where it is close to summit level. Exposed tops may feel chilly in the wind.

A windproof layer will help, with an extra warm layer for stops. Buffeting may affect balance on exposed ground, particularly near ridges and edges.

Rain timing may shift by several hours, which could change how much of the main walking period stays dry.

Cloud-free timing: Around 35% early, improving to around 45% later.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 1 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 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.

39/100

Afternoon · 12:00–17:00 Poor Winds ease compared with the morning. Summit winds around 15-25 mph in the early afternoon, easing to 10-20 mph later. 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.

49/100

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

Overnight · 17:00–08:00Wild campingBetaConditions look exceptional, but forecast uncertainty caps the grade at 88/100. 88/100Excellent · 600 m View detailsHide details

Night beginning Tuesday 22 September 2026

Full overnight outlook

Open-hillside camping looks very good overall around 600 m (88/100). It may be breezy on open ground, with gusts near 20 mph. Peak gusts range from about 10 mph at 300 m to 20 mph at 900 m. Little overnight rain is forecast. The coldest temperature falls from about 7.8°C at 300 m to 5.9°C at 900 m. Forecast models are not closely enough agreed for an exceptional grade. The grade is capped at 88/100.

Overnight rain0.0 mm Open ground · 600 m8 mph · gusts 15 mph Morning pack-upNo wet signal Sleeping-bag warmthISO comfort rating about 6°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 86%
Moonrise: 18:14 BST
Moonset: 02:34 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 m88/100 · very good

Wind / gust: 7 mph / 12 mph
Typical / low: 9.2°C / 7.8°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m88/100 · very good

Wind / gust: 8 mph / 15 mph
Typical / low: 9.2°C / 7.8°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

900 m88/100 · very good

Wind / gust: 10 mph / 20 mph
Typical / low: 7.0°C / 5.9°C · much of the night
In cloud: 13% of modelled night
Condensation: Low

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 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 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 Gritty psammite (Carn Mairg 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 Calcareous pelite, Graphitic pelite, 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 mphRain0.3 mm

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

Mapped rock across the summit and available routes Gritty psammite Carn Mairg Quartzite Formation

Origin: Metamorphic
Rock family: Quartzite
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

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.

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

quartzite, 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 Gritty psammite Carn Mairg Quartzite Formation 305–1,038 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Calcareous pelite Ben Lawers Schist Formation 513–828 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Graphitic pelite Ben Eagach Schist Formation Around 410 m Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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

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 Càrn Mairg 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 weather86/100Excellent

Wind5-20 mph northwesterly Gusts20-30 mph Feels like-2 to 2°C PrecipitationLittle or none Cloud-free summit estimate85% Freezing levelAbove summit DaylightSunrise 07:02 · Sunset 19:14 · 12.2 hours daylight

The day on the hill

Little rain and limited summit cloud on Càrn Mairg: summit wind broadly 5-20 mph, with gusts 20-30 mph at times (a moderate breeze).

Cloud & views

Cloud base around 1100–1400 m in the morning, then around 3000–3300 m around midday and 1000–1300 m by late afternoon. The summit is likely to stay mostly clear.

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

Rain & temperature

Little or no rain is forecast. Cold on exposed tops: air temperature broadly 2 to 6°C, feeling around -2 to 2°C in the wind.

Forecast confidence

Cloud height remains uncertain, especially where it is close to summit level. A windproof layer will help, with an extra warm layer for stops.

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 65% early, improving to around 75% later.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 4.2 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 0 h
Midday: Less than 1 hour
Later: 3 h

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

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

85/100

Afternoon · 12:00–17:00 Excellent Summit winds around 5-15 mph in the early afternoon, strengthening to 10-20 mph later. Gusts around 15-25 mph are possible on exposed ground.

87/100

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

Overnight · 17:00–08:00Wild campingBetaConditions look very good, but forecast uncertainty caps the grade at 88/100. 88/100Excellent · 600 m View detailsHide details

Night beginning Wednesday 23 September 2026

Full overnight outlook

Open-hillside camping looks very good overall around 600 m (88/100). 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 25 mph. Peak gusts range from about 20 mph at 300 m to 25 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 3.2°C at 900 m. Forecast models are not closely enough agreed for an exceptional grade. The grade is capped at 88/100.

Overnight rain0.0 mm Open ground · 600 m10 mph · gusts 21 mph Morning pack-upNo wet signal Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 92%
Moonrise: 18:22 BST
Moonset: 03:59 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 m88/100 · very good

Wind / gust: 8 mph / 18 mph
Typical / low: 6.6°C / 5.9°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m88/100 · very good

Wind / gust: 10 mph / 21 mph
Typical / low: 6.6°C / 5.9°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

900 m59/100 · mixed

Wind / gust: 11 mph / 25 mph
Typical / low: 4.2°C / 3.2°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 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 & scramblingBetaPatchy rain could leave exposed holds damp or slippery. Good82/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look good (82/100). Likely to stay mostly dry, but patchy rain remains possible and could leave exposed rock damp or slippery. The mapped summit rock is Gritty psammite (Carn Mairg 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 Calcareous pelite, Graphitic pelite, so rock character and wet-weather behaviour may change across the mountain.

Rock surfaceDry initially; rain possiblePeak gust23 mphRainPossible · 48%

Main concernrain possible despite mostly dry conditions being favoured

Mapped rock across the summit and available routes Gritty psammite Carn Mairg Quartzite Formation

Origin: Metamorphic
Rock family: Quartzite
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

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.

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

quartzite, 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 Gritty psammite Carn Mairg Quartzite Formation 305–1,038 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Calcareous pelite Ben Lawers Schist Formation 513–828 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Graphitic pelite Ben Eagach Schist Formation Around 410 m Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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

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 Càrn Mairg 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 weather47/100Poor

Wind30-50 mph southwesterly Gusts55-65 mph Feels like-8 to -4°C PrecipitationUp to around 2 mm Cloud-free summit estimate75% Cloud base through day1,100-1,700 m Freezing level900-1,200 m DaylightSunrise 07:04 · Sunset 19:11 · 12.1 hours daylight

The day on the hill

Strong gusts on Càrn Mairg: 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. Summit wind strength is uncertain: around 22-61 mph at walker height, with gusts 31-86 mph.

Check again nearer the time.

Cloud & views

Cloud base around 1100–1400 m in the morning, lifting to 1200–1500 m around midday and 1400–1700 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.

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 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.

Forecast confidence

Cloud height remains uncertain, especially where it is close to summit level. Keep windproof and warm layers readily available.

The strongest gusts could knock you over on exposed ground. Avoid exposed ridges and edges.

Summit wind could be roughly 22-61 mph, which changes how difficult exposed walking may feel.

Cloud-free timing: Best early at about 85%. Lowest around midday at about 65%.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 2.4 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.

Early: Less than 1 hour
Midday: 1.6 h
Later: 0 h

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

Morning · 08:00–12:00 Good Summit winds around 15-25 mph. Gusts around 25-35 mph are possible on exposed ground.

70/100

Afternoon · 12:00–17:00 Poor Winds strengthen compared with the morning. Summit winds around 30-45 mph. Gusts around 50-60 mph are possible on exposed ground. Walking into the wind is likely to be arduous, with buffeting that can knock you off balance. Summit cloud is more persistent early in this period, with better prospects later. Rain is possible during the afternoon, but forecast models disagree on whether it will fall.

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 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 6.2 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 8.3°C at 300 m to 5.4°C at 900 m.

Overnight rain6.2 mm Open ground · 600 m34 mph · gusts 56 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 97%
Moonrise: 18:28 BST
Moonset: 05:23 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: 28 mph / 46 mph
Typical / low: 10.4°C / 8.3°C · several hours
In cloud: 0% of modelled night
Condensation: Moderate

600 m9/100 · very poor

Wind / gust: 34 mph / 56 mph
Typical / low: 10.1°C / 7.7°C · several hours
In cloud: 53% of modelled night
Condensation: High

900 m0/100 · very poor

Wind / gust: 40 mph / 65 mph
Typical / low: 8.1°C / 5.4°C · much of the night
In cloud: 67% 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 Gritty psammite (Carn Mairg 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 Calcareous pelite, Graphitic pelite, 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 gust60 mphRain0.3 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 Gritty psammite Carn Mairg Quartzite Formation

Origin: Metamorphic
Rock family: Quartzite
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

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.

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

quartzite, 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 Gritty psammite Carn Mairg Quartzite Formation 305–1,038 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Calcareous pelite Ben Lawers Schist Formation 513–828 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Graphitic pelite Ben Eagach Schist Formation Around 410 m Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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

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.

Cross-check, don’t forecast-shop.

Compare the same day, height and time across sources. Don’t choose a forecast just because it suits your plan. If credible forecasts disagree, allow for the less favourable conditions and keep alternatives open.

Our forecast confidence is low for this day. Allow more room for conditions to differ. This describes our forecast uncertainty, not a live comparison with the services below.

The Met Office link opens this peak’s location forecast. Regional reports cover wider ground: check their area maps. Compare issue times and valid dates; links open the latest reports, not necessarily the day selected here. No affiliation or endorsement is implied.

How to use more than one mountain forecast

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

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

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

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

This is about Càrn Mairg 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 weather50/100Mixed

Wind25-35 mph westerly Gusts40-50 mph Feels like-4 to 0°C PrecipitationLittle or none Cloud-free summit estimate90% Cloud base through day1,400-2,200 m Freezing levelAbove summit DaylightSunrise 07:06 · Sunset 19:08 · 12.0 hours daylight

The day on the hill

On Càrn Mairg: summit wind broadly 25-35 mph, with gusts 40-50 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 1400–1700 m in the morning, lifting to 1900–2200 m around midday and 1800–2100 m by late afternoon. The summit is likely to stay mostly clear.

Cloud may hang lower on western slopes and lift somewhat on the eastern side, but local terrain can differ.

Rain & temperature

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 models differ on summit wind strength: around 18-37 mph at walker height, with gusts 25-52 mph.

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. Summit wind could be roughly 18-37 mph, which changes how difficult exposed walking may feel.

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.

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 25-35 mph. Gusts around 40-50 mph are possible on exposed ground. Buffeting may affect balance on exposed ground, particularly near ridges and edges. Summit cloud becomes more persistent later.

49/100

Afternoon · 12:00–17:00 Mixed Summit 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.

52/100

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

Overnight · 17:00–08:00Wild campingBetaGusts near 40 mph make meaningful shelter important. 59/100Mixed · 600 m View detailsHide details

Night beginning Friday 25 September 2026

Full overnight outlook

Open-hillside camping looks mixed overall around 600 m (59/100). A lower pitch near 300 m looks more comfortable. Conditions are less suitable by 900 m. Open-ground gusts may reach about 40 mph. Seek meaningful shelter. Peak gusts range from about 30 mph at 300 m to 40 mph at 900 m. Little overnight rain is forecast. Pitches near 600 and 900 m may spend part of the night in cloud, bringing damp conditions and poor visibility while cloud is present. The coldest temperature falls from about 7.1°C at 300 m to 5.2°C at 900 m.

Overnight rain0.0 mm Open ground · 600 m20 mph · gusts 34 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Near-full moon

Illuminated disc: 99%
Moonrise: 18:34 BST
Moonset: 06:49 next morning BST

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

Overnight window: 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: 17 mph / 28 mph
Typical / low: 7.6°C / 7.1°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m59/100 · mixed

Wind / gust: 20 mph / 34 mph
Typical / low: 7.5°C / 7.0°C · much of the night
In cloud: 40% of modelled night
Condensation: Moderate

900 m39/100 · poor

Wind / gust: 23 mph / 39 mph
Typical / low: 5.5°C / 5.2°C · much of the night
In cloud: 67% of modelled night
Condensation: Moderate

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 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 & scramblingBetaRock may be damp or still drying. Gusts near 45 mph may affect balance on exposed rock. Poor30/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look poor (30/100). Some rock may still be damp or drying, especially on polished slabs and vegetated sections. The mapped summit rock is Gritty psammite (Carn Mairg 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 Calcareous pelite, Graphitic pelite, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 45 mph. Crosswinds can make exposed ridges substantially more serious.

Rock surfaceDamp or dryingPeak gust44 mphRainPossible · 42%

Main factorsgusts around 45 mphdamp or incompletely dried rock possible

Mapped rock across the summit and available routes Gritty psammite Carn Mairg Quartzite Formation

Origin: Metamorphic
Rock family: Quartzite
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

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.

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

quartzite, 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 Gritty psammite Carn Mairg Quartzite Formation 305–1,038 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Calcareous pelite Ben Lawers Schist Formation 513–828 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Graphitic pelite Ben Eagach Schist Formation Around 410 m Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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

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 Càrn Mairg 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: Unavailable

Overall hill weather46/100Poor

Wind20-30 mph southwesterly Gusts30-40 mph Feels like-6 to -2°C PrecipitationLittle or none Cloud-free summit estimate50% Cloud base through day500-2,200 m Freezing level900-1,200 m DaylightSunrise 07:08 · Sunset 19:05 · 11.9 hours daylight

The day on the hill

Frequent summit cloud on Càrn Mairg: summit wind broadly 20-30 mph, with gusts 30-40 mph at times (a fresh breeze). Patchy mist is possible in sheltered valleys early on.

Wind & exposure

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

Cloud & views

Cloud base around 500–800 m in the morning, lifting to 700–1000 m around midday and 1900–2200 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 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.

Rain & temperature

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 disagree markedly on summit wind strength. Check again nearer the time.

Keep windproof and warm layers readily available.

Forecast confidence

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 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.

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 30-40 mph are possible on exposed ground.

48/100

Afternoon · 12:00–17:00 Poor Summit winds around 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Summit cloud is more persistent early in this period, with better prospects later.

45/100

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 55 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 m View detailsHide details

Night beginning Saturday 26 September 2026

Full overnight outlook

Exposed camping is not recommended near 600 and 900 m: gusts may reach about 55 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 55 mph at 900 m. Roughly 5.7 mm is forecast overnight, 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 7.7°C at 300 m to 5.9°C at 900 m.

Overnight rain5.7 mm Open ground · 600 m28 mph · gusts 49 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Near-full moon

Illuminated disc: 100%
Moonrise: 18:39 BST
Moonset: Outside this window

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: 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 m39/100 · poor

Wind / gust: 23 mph / 41 mph
Typical / low: 8.8°C / 7.7°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: 8.7°C / 7.7°C · much of the night
In cloud: 7% of modelled night
Condensation: Moderate

900 m9/100 · very poor

Wind / gust: 32 mph / 57 mph
Typical / low: 6.7°C / 5.9°C · much of the night
In cloud: 60% of modelled night
Condensation: High

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 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.

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Daytime · exposed rockClimbing & scramblingBetaGusts near 35 mph may affect balance on exposed rock. Mixed66/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look fair (66/100). Rock is likely to be mostly dry, though seepage and shaded holds are not resolved. The mapped summit rock is Gritty psammite (Carn Mairg 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 Calcareous pelite, Graphitic pelite, 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 surfaceProbably dryPeak gust34 mphRain0.0 mm

Main factorsgusts around 35 mphmuch of the route may be in cloud

Mapped rock across the summit and available routes Gritty psammite Carn Mairg Quartzite Formation

Origin: Metamorphic
Rock family: Quartzite
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

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.

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

quartzite, 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 Gritty psammite Carn Mairg Quartzite Formation 305–1,038 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Calcareous pelite Ben Lawers Schist Formation 513–828 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Graphitic pelite Ben Eagach Schist Formation Around 410 m Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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

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 Càrn Mairg 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 weather42/100Poor

Wind25-40 mph southwesterly Gusts40-50 mph Feels like-4 to 0°C PrecipitationUp to around 2 mm Cloud-free summit estimate70% Cloud base through day600-1,700 m Freezing levelAbove summit DaylightSunrise 07:10 · Sunset 19:03 · 11.9 hours daylight

The day on the hill

Strong gusts on Càrn Mairg: summit wind broadly 25-40 mph, with gusts 40-50 mph at times (strong winds).

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 600–900 m in the morning, lifting to 1400–1700 m around midday. 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 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. The forecast total is up to around 2 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.

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.

If clothing gets wet, you can cool more quickly. Keep a dry warm layer protected.

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 10.9 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 2 h
Midday: 4 h
Later: 2.9 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. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period.

27/100

Afternoon · 12:00–17:00 Mixed Summit 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.

56/100

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

Overnight · 17:00–08:00Wild campingBetaGusts near 35 mph make meaningful shelter important. 59/100Mixed · 600 m View detailsHide details

Night beginning Sunday 27 September 2026

Full overnight outlook

Open-hillside camping looks mixed overall around 600 m (59/100). A lower pitch near 300 m looks more comfortable. Conditions are less suitable by 900 m. Open-ground gusts may reach about 35 mph. Seek meaningful shelter. Peak gusts range from about 25 mph at 300 m to 35 mph at 900 m. A little rain may coincide with pitching or 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 900 m. Ventilation will matter. The coldest temperature falls from about 6.3°C at 300 m to 4.5°C at 900 m.

Overnight rain0.8 mm Open ground · 600 m18 mph · gusts 30 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Waning gibbous moon

Illuminated disc: 98%
Moonrise: 18:45 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 m75/100 · promising

Wind / gust: 15 mph / 25 mph
Typical / low: 6.7°C / 6.3°C · much of the night
In cloud: 0% of modelled night
Condensation: Moderate

600 m59/100 · mixed

Wind / gust: 18 mph / 30 mph
Typical / low: 6.7°C / 6.3°C · much of the night
In cloud: 0% of modelled night
Condensation: Moderate

900 m39/100 · poor

Wind / gust: 22 mph / 35 mph
Typical / low: 5.0°C / 4.5°C · much of the night
In cloud: 47% of modelled night
Condensation: High

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

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

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

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 45 mph may affect balance on exposed rock. Poor10/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look very poor (10/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Gritty psammite (Carn Mairg 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 Calcareous pelite, Graphitic pelite, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 45 mph. Crosswinds can make exposed ridges substantially more serious.

Rock surfaceWet rock likelyPeak gust46 mphRain1.1 mm

Main factorsgusts around 45 mphwet rock likely

Mapped rock across the summit and available routes Gritty psammite Carn Mairg Quartzite Formation

Origin: Metamorphic
Rock family: Quartzite
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Moderate confidence

View the summit BGS record

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.

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

quartzite, 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 Gritty psammite Carn Mairg Quartzite Formation 305–1,038 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Calcareous pelite Ben Lawers Schist Formation 513–828 m samples Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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 Graphitic pelite Ben Eagach Schist Formation Around 410 m Seen on Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

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

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 Càrn Mairg 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

Càrn Mairg 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

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

3 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

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

3 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

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

3 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

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

3 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

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

3 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

Càrn Gorm, Meall Garbh (Càrn Mairg), Càrn Mairg and Creag Mhòr (Meall na Aighean)

3 rock types appear across the available route samples

After dark: aurora and stargazing

The day on the hill

Wind & exposure

Cloud & views