Mountain Weather

Beinn Iutharn Mhòr weather forecast.

1,045 m summit in Angus Glens. 7 forecast days covering wind, cloud, rain and temperature, updated 21 September 2026 at 16:08 UTC.

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Confidence: Medium
Overall hill weather36/100Poor
Wind20-35 mph southwesterly Gusts35-45 mph Feels like2 to 6°C PrecipitationAround 2-5 mm Cloud-free summit estimate10% Cloud base through day600-900 m Freezing levelAbove summit DaylightSunrise 06:58 · Sunset 19:14 · 12.3 hours daylight

The day on the hill

Frequent summit cloud on Beinn Iutharn Mhòr: 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 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 at times. The forecast total is around 2-5 mm, but local amounts will vary.

Forecast models differ on summit wind strength: around 21-34 mph at walker height, with gusts 29-48 mph. Exposed tops may feel chilly in the wind.

A windproof layer will help, with an extra warm layer for stops. If clothing gets wet, you can cool more quickly.

Keep a dry warm layer protected. Buffeting may affect balance on exposed ground, particularly near ridges and edges.

Forecast confidence

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 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 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. Rain is possible during the main walking period, but its timing may shift by several hours.
35/100
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. Rain is possible during the main walking period, but its timing may shift by several hours.
36/100

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

Overnight · 17:00–08:00Wild campingBetaAbout 16.9 mm is forecast, with rain liable to affect both pitching and packing up. 39/100Poor · 600 m View detailsHide details
Night beginning Tuesday 22 September 2026

Full overnight outlook

Open-hillside camping looks poor overall around 600 m (39/100). 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. Roughly 16.9 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 7.2°C at 300 m to 5.3°C at 900 m.

Overnight rain16.9 mm Open ground · 600 m12 mph · gusts 25 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc
86%
Moonrise
18:13 BST
Moonset
02:30 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 m39/100 · poor
Wind / gust
10 mph / 20 mph
Typical / low
9.9°C / 7.2°C · several hours
In cloud
0% of modelled night
Condensation
High
600 m39/100 · poor
Wind / gust
12 mph / 25 mph
Typical / low
9.9°C / 7.2°C · several hours
In cloud
0% of modelled night
Condensation
High
900 m39/100 · poor
Wind / gust
14 mph / 29 mph
Typical / low
8.1°C / 5.3°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 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

Approximate height is enough, please do not share an exact wild-camp location.

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 Pebbly quartzite (An Socach 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 Lamprophyre, 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 gust38 mphRain2.9 mm
Main factorsgusts around 40 mphwet rock likelymuch of the route may be in cloud
Mapped rock across the summit and available routes Pebbly quartzite An Socach 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 Bhac and Beinn Iutharn Mhòr

quartzite, granite, gneiss or gabbro, limestone

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 Pebbly quartzite An Socach Quartzite Formation 693–1,041 m samples Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Lamprophyre North Britain Siluro-Devonian Calc-Alkaline Dyke Suite Around 955 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Sron Nan Dias Pelite And Limestone Formation Around 598 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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

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

A broad surface report is enough; you do not need to identify a particular route.

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 Beinn Iutharn Mhòr 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

Confidence: Medium
Overall hill weather81/100Good
Wind10-25 mph northwesterly Gusts20-30 mph Feels like-4 to 0°C PrecipitationUp to around 2 mm Cloud-free summit estimate65% Cloud base through day1,000-2,200 m Freezing levelAbove summit DaylightSunrise 07:00 · Sunset 19:11 · 12.2 hours daylight

The day on the hill

Mostly dry with limited summit cloud on Beinn Iutharn Mhòr: summit wind broadly 10-25 mph, with gusts 20-30 mph at times (a moderate breeze).

Cloud & views

Cloud base around 1000–1300 m through the morning, lifting to 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 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 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

Some rain is likely, totalling up to around 2 mm, but its timing and local amounts are uncertain. Cold on exposed tops: air temperature broadly 2 to 6°C, feeling around -4 to 0°C in the wind.

Forecast confidence

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

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

Cloud-free timing: Around 30% early, improving to around 95% later.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 5.7 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early
0 h
Midday
1.8 h
Later
3 h

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

Morning · 08:00–12:00 Good Summit winds around 10-20 mph. Gusts around 20-30 mph are possible on exposed ground. Rain is forecast during this period.
74/100
Afternoon · 12:00–17:00 Excellent Summit winds around 10-20 mph. Gusts around 20-30 mph are possible on exposed ground. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period.
88/100

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

Overnight · 17:00–08:00Wild campingBetaLower pitches look more comfortable than exposed ground near 900 m. 87/100Excellent · 600 m View detailsHide details
Night beginning Wednesday 23 September 2026

Full overnight outlook

Open-hillside camping looks promising overall around 600 m (87/100). 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.

Overnight rain0.0 mm Open ground · 600 m9 mph · gusts 22 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
18:21 BST
Moonset
03:55 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 / 19 mph
Typical / low
6.7°C / 5.7°C · much of the night
In cloud
0% of modelled night
Condensation
Low
600 m87/100 · promising
Wind / gust
9 mph / 22 mph
Typical / low
6.7°C / 5.7°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
4.9°C / 4.4°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

Approximate height is enough, please do not share an exact wild-camp location.

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Poor30/100 View detailsHide details
Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look poor (30/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Pebbly quartzite (An Socach 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 Lamprophyre, Pelite, so rock character and wet-weather behaviour may change across the mountain.

Rock surfaceWet rock likelyPeak gust25 mphRain0.5 mm
Main concernwet rock likely
Mapped rock across the summit and available routes Pebbly quartzite An Socach 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 Bhac and Beinn Iutharn Mhòr

quartzite, granite, gneiss or gabbro, limestone

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 Pebbly quartzite An Socach Quartzite Formation 693–1,041 m samples Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Lamprophyre North Britain Siluro-Devonian Calc-Alkaline Dyke Suite Around 955 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Sron Nan Dias Pelite And Limestone Formation Around 598 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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

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

A broad surface report is enough; you do not need to identify a particular route.

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 Beinn Iutharn Mhòr 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

Confidence: Medium
Overall hill weather52/100Mixed
Wind25-40 mph southwesterly Gusts45-55 mph Feels like-4 to 0°C PrecipitationLittle or none Cloud-free summit estimate90% Cloud base through day1,400-2,000 m Freezing level1,000-1,300 m DaylightSunrise 07:02 · Sunset 19:09 · 12.1 hours daylight

The day on the hill

Strong gusts on Beinn Iutharn Mhòr: summit wind broadly 25-40 mph, with gusts 45-55 mph at times (strong winds).

Wind & exposure

Much calmer lower down - generally 10-20 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 1400–1700 m in the morning, then around 1700–2000 m around midday and 1400–1700 m by late afternoon. The summit is likely to stay mostly clear.

Cloud may hang lower on southwestern slopes and lift somewhat on the northeastern 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 27-43 mph at walker height, with gusts 38-60 mph. Keep windproof and warm layers readily available.

Forecast confidence

Summit wind could be roughly 27-43 mph, which changes how difficult exposed walking may feel.

Cloud-free timing: Best around midday at about 95%. Lowest later at about 85%.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 3.5 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early
1 h
Midday
1 h
Later
Less than 1 hour

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 early in the morning, strengthening to 20-30 mph later. Gusts around 35-45 mph are possible on exposed ground. Buffeting may affect balance on exposed ground, particularly near ridges and edges.
58/100
Afternoon · 12:00–17:00 Poor Winds strengthen compared with the morning. 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.
46/100

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

Overnight · 17:00–08:00Wild campingBetaExposed camping is not recommended near 300, 600 and 900 m: gusts may reach about 60 mph. Sustained winds may reach about 45 mph at times. Choose an alternative off the exposed hill. Do not rely on finding shelter after setting out. 9/100Poor · 600 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 60 mph. Sustained winds may reach about 45 mph at times. Choose an alternative off the exposed hill. Do not rely on finding shelter after setting out. Open-hillside camping looks very poor overall around 600 m (9/100). Peak gusts range from about 45 mph at 300 m to 60 mph at 900 m. Around 3 mm is forecast, including rain around pack-up. Pitches near 600 and 900 m may spend part of the night in cloud, bringing damp conditions and poor visibility while cloud is present. Condensation risk is high near 300, 600 and 900 m. Ventilation will matter. The coldest temperature falls from about 7.6°C at 300 m to 5.6°C at 900 m.

Overnight rain3.0 mm Open ground · 600 m30 mph · gusts 53 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc
97%
Moonrise
18:26 BST
Moonset
05:21 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 / 44 mph
Typical / low
9.7°C / 7.6°C · much of the night
In cloud
0% of modelled night
Condensation
High
600 m9/100 · very poor
Wind / gust
30 mph / 53 mph
Typical / low
9.5°C / 7.3°C · much of the night
In cloud
73% of modelled night
Condensation
High
900 m9/100 · very poor
Wind / gust
36 mph / 62 mph
Typical / low
7.5°C / 5.6°C · much of the night
In cloud
80% of modelled night
Condensation
High

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

Approximate height is enough, please do not share an exact wild-camp location.

Daytime · exposed rockClimbing & scramblingBetaRock may be damp or still drying. Gusts near 45 mph may affect balance on exposed rock. Poor9/100 View detailsHide details
Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look very poor (9/100). Recent rain may leave seepage and damp rock, especially on shaded sections. The mapped summit rock is Pebbly quartzite (An Socach 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 Lamprophyre, 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 surfaceDry overhead; seepage uncertainPeak gust47 mphRainPossible · 70%
Main factorsgusts around 45 mphdamp or incompletely dried rock possible
Mapped rock across the summit and available routes Pebbly quartzite An Socach 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 Bhac and Beinn Iutharn Mhòr

quartzite, granite, gneiss or gabbro, limestone

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 Pebbly quartzite An Socach Quartzite Formation 693–1,041 m samples Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Lamprophyre North Britain Siluro-Devonian Calc-Alkaline Dyke Suite Around 955 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Sron Nan Dias Pelite And Limestone Formation Around 598 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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

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

A broad surface report is enough; you do not need to identify a particular route.

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 Beinn Iutharn Mhòr 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

Confidence: Medium
Overall hill weather58/100Mixed
Wind15-25 mph southwesterly Gusts25-35 mph Feels like-4 to 0°C PrecipitationUp to around 2 mm Cloud-free summit estimate35% Cloud base through day500-1,700 m Freezing levelAbove summit DaylightSunrise 07:04 · Sunset 19:06 · 12.0 hours daylight

The day on the hill

Frequent summit cloud on Beinn Iutharn Mhòr: summit wind broadly 15-25 mph, with gusts 25-35 mph at times (a fresh breeze).

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 1000–1300 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 during the afternoon.

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 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 6°C, feeling around -4 to 0°C in the wind. Forecast models differ on summit wind strength: around 11-29 mph at walker height, with gusts 15-41 mph.

Forecast confidence

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

Summit wind could be roughly 11-29 mph, which changes how difficult exposed walking may feel.

Cloud-free timing: Around 5% early, improving to around 50% later.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 10.2 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
2 h
Midday
3.2 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.
49/100
Afternoon · 12:00–17:00 Mixed Summit winds around 15-25 mph. Gusts around 20-30 mph are possible on exposed ground. Summit cloud is more persistent early in this period, with better prospects later.
66/100

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 Friday 25 September 2026

Full overnight outlook

Exposed camping is not recommended near 900 m: gusts may reach about 45 mph. Sustained winds may reach about 30 mph at times. Lower sheltered ground may be less exposed, but this forecast does not confirm a suitable pitch or a safe approach. Check its overnight conditions separately. Open-hillside camping looks poor overall around 600 m (39/100). Peak gusts range from about 30 mph at 300 m to 45 mph at 900 m. 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. Condensation risk is high near 300, 600 and 900 m. Ventilation will matter. The coldest temperature falls from about 6.9°C at 300 m to 4.8°C at 900 m.

Overnight rain0.2 mm Open ground · 600 m22 mph · gusts 37 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Near-full moon

Illuminated disc
99%
Moonrise
18:31 BST
Moonset
06:47 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
18 mph / 31 mph
Typical / low
7.1°C / 6.9°C · much of the night
In cloud
0% of modelled night
Condensation
High
600 m39/100 · poor
Wind / gust
22 mph / 37 mph
Typical / low
6.9°C / 6.7°C · much of the night
In cloud
93% of modelled night
Condensation
High
900 m19/100 · very poor
Wind / gust
26 mph / 44 mph
Typical / low
5.0°C / 4.8°C · several hours
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

Approximate height is enough, please do not share an exact wild-camp location.

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 30 mph may affect balance on exposed rock. Poor18/100 View detailsHide details
Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look very poor (18/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Pebbly quartzite (An Socach 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 Lamprophyre, Pelite, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 30 mph. Crosswinds can make exposed ridges substantially more serious. Cloud may also make route-finding and retreat harder.

Rock surfaceWet rock likelyPeak gust32 mphRain0.3 mm
Main factorsgusts around 30 mphwet rock likelymuch of the route may be in cloud
Mapped rock across the summit and available routes Pebbly quartzite An Socach 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 Bhac and Beinn Iutharn Mhòr

quartzite, granite, gneiss or gabbro, limestone

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 Pebbly quartzite An Socach Quartzite Formation 693–1,041 m samples Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Lamprophyre North Britain Siluro-Devonian Calc-Alkaline Dyke Suite Around 955 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Sron Nan Dias Pelite And Limestone Formation Around 598 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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

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

A broad surface report is enough; you do not need to identify a particular route.

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 Beinn Iutharn Mhòr 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

Confidence: Medium
Overall hill weather24/100Poor
Wind25-35 mph southwesterly Gusts40-50 mph Feels like-4 to 0°C PrecipitationAround 2-5 mm Cloud-free summit estimate10% Cloud base through day500-1,000 m Freezing levelAbove summit DaylightSunrise 07:06 · Sunset 19:03 · 11.9 hours daylight

The day on the hill

A wet day with extensive summit cloud on Beinn Iutharn Mhòr: summit wind broadly 25-35 mph, with gusts 40-50 mph at times (strong winds).

Wind & exposure

Much calmer lower down - generally 10-20 mph in the valley, rising towards the tops.

Cloud & views

Cloud base around 500–800 m through the morning, lifting to 700–1000 m by late afternoon. Summit cloud is likely, but brief clear spells remain possible if the cloud sits higher than expected.

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

Cloud may hang lower on southwestern slopes and lift somewhat on the northeastern side, but local terrain can differ. Any sunshine may be confined to lower ground or breaks away from the summit.

Drizzle is forecast for much of the day. The forecast total is around 2-5 mm, but local amounts will vary.

Cold on exposed tops: air temperature broadly 2 to 6°C, feeling around -4 to 0°C in the wind. Forecast models differ on summit wind strength: around 17-38 mph at walker height, with gusts 24-53 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.

Buffeting may affect balance on exposed ground, particularly near ridges and edges. Rain could reach the main walking period or hold off until later. Forecast models disagree on the timing.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 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
0.8 h
Midday
3.3 h
Later
2.7 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. Rain is forecast during this period.
24/100
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. Rain is forecast during this period. Rain is possible during the afternoon, but forecast models disagree on whether it will fall.
25/100

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 Saturday 26 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 3 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 300, 600 and 900 m. Ventilation will matter. The coldest temperature falls from about 9.1°C at 300 m to 6.8°C at 900 m.

Overnight rain3.0 mm Open ground · 600 m23 mph · gusts 36 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 6°C or lower

Moon overnight

Near-full moon

Illuminated disc
100%
Moonrise
18:36 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 m59/100 · mixed
Wind / gust
19 mph / 30 mph
Typical / low
9.7°C / 9.1°C · much of the night
In cloud
0% of modelled night
Condensation
High
600 m39/100 · poor
Wind / gust
23 mph / 36 mph
Typical / low
9.4°C / 8.7°C · much of the night
In cloud
93% of modelled night
Condensation
High
900 m19/100 · very poor
Wind / gust
27 mph / 42 mph
Typical / low
7.6°C / 6.8°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

Approximate height is enough, please do not share an exact wild-camp location.

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 45 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 Pebbly quartzite (An Socach 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 Lamprophyre, 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. Cloud may also make route-finding and retreat harder.

Rock surfaceWet rock likelyPeak gust43 mphRain2.7 mm
Main factorsgusts around 45 mphwet rock likelymuch of the route may be in cloud
Mapped rock across the summit and available routes Pebbly quartzite An Socach 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 Bhac and Beinn Iutharn Mhòr

quartzite, granite, gneiss or gabbro, limestone

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 Pebbly quartzite An Socach Quartzite Formation 693–1,041 m samples Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Lamprophyre North Britain Siluro-Devonian Calc-Alkaline Dyke Suite Around 955 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Sron Nan Dias Pelite And Limestone Formation Around 598 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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

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

A broad surface report is enough; you do not need to identify a particular route.

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 Beinn Iutharn Mhòr 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

Confidence: Unavailable
Overall hill weather38/100Poor
Wind15-30 mph southerly Gusts30-40 mph Feels like-2 to 2°C PrecipitationUp to around 2 mm Cloud-free summit estimate25% Cloud base through day500-1,200 m Freezing levelAbove summit DaylightSunrise 07:08 · Sunset 19:00 · 11.9 hours daylight

The day on the hill

Light rain for several hours on Beinn Iutharn Mhòr: summit wind broadly 15-30 mph, with gusts 30-40 mph at times (a fresh breeze).

Cloud & views

Cloud base around 500–800 m in the morning, then around 900–1200 m around midday and 500–800 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 southern slopes and lift somewhat on the northern 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. The forecast total is up to around 2 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 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.

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: Around 5% early, improving to around 15% later.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 6 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Cloud may obscure this summit even while the surrounding model grid indicates sunshine. The low cloud-free summit estimate is a reason to be cautious about expecting views.

Early
0 h
Midday
2.1 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. Rain is forecast during this period.
34/100
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.
41/100

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. 54/100Mixed · 600 m View detailsHide details
Night beginning Sunday 27 September 2026

Full overnight outlook

Open-hillside camping looks mixed overall around 600 m (54/100). 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. Wind direction may change substantially during the night. Shelter that works at dusk may be less effective later. Around 1.6 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 300, 600 and 900 m. Ventilation will matter.

Overnight rain1.6 mm Open ground · 600 m20 mph · gusts 29 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Waning gibbous moon

Illuminated disc
98%
Moonrise
18:42 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: 27 Sep, 17:00 BST to 28 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m64/100 · reasonable
Wind / gust
16 mph / 24 mph
Typical / low
9.4°C / 5.7°C · much of the night
In cloud
0% of modelled night
Condensation
High
600 m54/100 · mixed
Wind / gust
20 mph / 29 mph
Typical / low
8.9°C / 5.7°C · much of the night
In cloud
60% of modelled night
Condensation
High
900 m39/100 · poor
Wind / gust
23 mph / 35 mph
Typical / low
7.1°C / 4.4°C · several hours
In cloud
100% of modelled night
Condensation
High

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

Approximate height is enough, please do not share an exact wild-camp location.

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 35 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). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Pebbly quartzite (An Socach 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 Lamprophyre, 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 surfaceWet rock likelyPeak gust33 mphRain1.0 mm
Main factorsgusts around 35 mphwet rock likelymuch of the route may be in cloud
Mapped rock across the summit and available routes Pebbly quartzite An Socach 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 Bhac and Beinn Iutharn Mhòr

quartzite, granite, gneiss or gabbro, limestone

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 Pebbly quartzite An Socach Quartzite Formation 693–1,041 m samples Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Lamprophyre North Britain Siluro-Devonian Calc-Alkaline Dyke Suite Around 955 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Sron Nan Dias Pelite And Limestone Formation Around 598 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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

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

A broad surface report is enough; you do not need to identify a particular route.

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 Beinn Iutharn Mhòr 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

Confidence: Unavailable
Overall hill weather56/100Mixed
Wind20-30 mph southwesterly Gusts30-40 mph Feels like-4 to 0°C PrecipitationUp to around 2 mm Cloud-free summit estimate70% Cloud base through day700-1,700 m Freezing levelAbove summit DaylightSunrise 07:10 · Sunset 18:58 · 11.8 hours daylight

The day on the hill

On Beinn Iutharn Mhòr: summit wind broadly 20-30 mph, with gusts 30-40 mph at times (a fresh breeze).

Cloud & views

Cloud base around 700–1000 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. Keep windproof and warm layers readily available.

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

Forecast confidence

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 9.1 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.

Early
Less than 1 hour
Midday
3.9 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 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period.
44/100
Afternoon · 12:00–17:00 Mixed Summit winds around 15-25 mph. Gusts around 25-35 mph are possible on exposed ground. Rain is forecast during this period.
69/100

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 Monday 28 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. 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 it looks cold for several hours, rather than only dipping briefly to 4.8°C.

Overnight rain0.2 mm Open ground · 600 m19 mph · gusts 30 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Waning gibbous moon

Illuminated disc
94%
Moonrise
18:50 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 m64/100 · reasonable
Wind / gust
16 mph / 25 mph
Typical / low
5.3°C / 4.8°C · several hours
In cloud
0% of modelled night
Condensation
High
600 m59/100 · mixed
Wind / gust
19 mph / 30 mph
Typical / low
5.3°C / 4.8°C · several hours
In cloud
0% of modelled night
Condensation
High
900 m39/100 · poor
Wind / gust
22 mph / 35 mph
Typical / low
4.2°C / 3.9°C · much of the night
In cloud
80% of modelled night
Condensation
High

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

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Approximate height is enough, please do not share an exact wild-camp location.

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 35 mph may affect balance on exposed rock. Poor45/100 View detailsHide details
Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look mixed (45/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Pebbly quartzite (An Socach 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 Lamprophyre, 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.

Rock surfaceWet rock likelyPeak gust33 mphRain1.6 mm
Main factorsgusts around 35 mphwet rock likely
Mapped rock across the summit and available routes Pebbly quartzite An Socach 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 Bhac and Beinn Iutharn Mhòr

quartzite, granite, gneiss or gabbro, limestone

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 Pebbly quartzite An Socach Quartzite Formation 693–1,041 m samples Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Lamprophyre North Britain Siluro-Devonian Calc-Alkaline Dyke Suite Around 955 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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 Sron Nan Dias Pelite And Limestone Formation Around 598 m Seen on Càrn Bhac and Beinn Iutharn Mhòr

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

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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A broad surface report is enough; you do not need to identify a particular route.

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

After dark: aurora and stargazing

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

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

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

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

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Weather data: Open-Meteo (CC BY 4.0). Adapted by Mountain Weather.

Forecast run: 2026-09-21

Keep exploring

Weather around Beinn Iutharn Mhòr.

Compare the summit forecast with the wider regional picture and nearby peaks before choosing a route.

Regional mountain forecastAngus GlensView area →
Càrn an Rìgh1,029 m · 2.6 km awayForecast →Glas Tulaichean1,051 m · 3.3 km awayForecast →An Socach (Braemar)944 m · 3.4 km awayForecast →Càrn Bhac946 m · 4.0 km awayForecast →

A forecast is part of the decision.

Mountain weather can differ sharply from conditions in the valley. Check official warnings, carry appropriate navigation and clothing, and be ready to change the plan. Read how Mountain Weather forecasts are produced and where their limits lie.

Choose another summit