Cadair Idris - Penygadair (Cader Idris) Weather Forecast – 893m, Mid Wales and Cambrian Mountains

Thursday 3 September 2026Medium confidence

Overall hill weather22/100Poor

Wind33 mph SW Gusts46 mph Feels8°C Rain0.1 mm Cloud-free summit25% Cloud base through day500–1,100 m Freezing levelAbove summit Daylight06:28–20:00 · 13.5 h

Forecast confidence: Rain could reach the main walking period or hold off until later; forecast models disagree on the timing.

A rough, clagged-in day on Cadair Idris - Penygadair: summit wind broadly 20-40 mph, with gusts 40-50 mph during the evening (gale-force winds). Much calmer lower down - generally 10-20 mph in the valley, rising towards the tops. Cloud base around 800-1100 m in the morning, lowering to 500-800 m around midday. Expect the top to stay in cloud for most or all of daylight, with no dependable break. Cloud height is close to summit level at times, so small local changes could put the top in or out of cloud. Cloud is likely to hang lowest on southwestern slopes; the northeastern side should see somewhat higher bases and better breaks. Very little direct sunshine is indicated; cloud is likely to remain extensive. Little or no rain expected. Confidence moderate (forecast models agree on the walking impact of the wind) - walker-height summit wind could reasonably be 30-35 mph, with gusts 42-49 mph. Cloud base is the least certain part of this - it could sit a couple of hundred metres either way, especially where it is close to summit level.

At this mountain

Sunshine and sky

Extensive cloud. Cloud is likely to remain extensive for much of the day.

Modelled sunshineLess than 1 hour3% of daylight

Early0 h sunshine

MiddayLess than 1 hour sunshine

Later0 h sunshine

These are direct modelled sunshine hours during daylight, not the probability of sunshine. Cloud cover and summit cloud are assessed separately in the forecast above. Local hill cloud can still make an individual summit brighter or duller than the surrounding model grid.

Morning · 07:00–13:00Poor

31/100

Afternoon & evening · 13:00–22:00Poor

13/100

Separate hill-weather grades help compare an early start with later conditions; the main daytime forecast above still covers the core walking day.

Overnight · 6 p.m.–9 a.m.Wild campingBetaGusts near 70 mph make meaningful shelter important. 24/100Poor · 600 m View detailsHide details

Night beginning Thursday 3 September 2026

Full overnight outlook

Open-hillside camping looks poor overall around 600 m (24/100). A lower pitch near 300 m looks more comfortable; conditions are less suitable by 900 m. Open-ground gusts may reach about 70 mph, making exposed pitches a poor choice. Peak gusts increase from about 50 mph at 300 m to 70 mph at 900 m. A wet night is likely, with roughly 35.8 mm; the wettest inconvenience is most likely around pack-up. From around 600 m upward, pitches may spend part of the night in cloud, with high condensation risk, persistent damp and poor visibility; ventilation will matter. The coldest temperature falls from about 11.3°C at 300 m to 8.9°C at 900 m.

Overnight rain36 mm Open ground · 600 m28 mph · gusts 58 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 8°C or lower

Elevation reference (open ground)

300 m39/100 · poor

Wind / gust: 23 / 49 mph
Typical / low: 13.8° / 11.3°C
In cloud: Unlikely
Condensation: High

600 m24/100 · poor

Wind / gust: 28 / 58 mph
Typical / low: 13.4° / 10.7°C
In cloud: 31% of night
Condensation: High

900 m24/100 · poor

Wind / gust: 33 / 69 mph
Typical / low: 11.6° / 8.9°C · several hours
In cloud: 100% of 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 & scramblingBetaGusts near 45 mph increase the seriousness of exposed ground. 0/100Poor · Very poor View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look very poor (0/100). Some rock may still be damp or drying; polished slabs and vegetated sections could be notably worse. The mapped summit rock is Tuff and lava (Pen y gadair Volcanic Formation). Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery. Representative samples along available mapped routes also include Microgranite, Mudstone and 4 other mapped types, 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 surfaceDamp or dryingPeak gust46 mphRainPossible · 95%

Main factorsgusts around 45 mphdamp or incompletely dried rock possiblemuch of the route may be in cloud

Mapped rock across the summit and available routes Tuff and lava Pen y gadair Volcanic Formation

Origin: Igneous
Rock family: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Low confidence

View the summit BGS record

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them 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.

Mapped variation

8 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 Tuff and lava Pen y gadair Volcanic Formation Around 844 m Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Microgranite Unnamed Igneous Intrusion, Ordovician 162–676 m samples Seen on Peak Cadair Idris Pony Path

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 Mudstone Ty'r Gawen Mudstone Formation 388–762 m samples Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Felsic tuff Craig Cau Formation 198–286 m samples Seen on Peak Cadair Idris Minffordd

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Basalt Unnamed Igneous Intrusion, Ordovician Around 250 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Mudstone and siltstone Ceiswyn Formation Around 105 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Tuff and lava Llyn y Gafr Volcanic Formation Around 332 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock Ty'r Gawen Mudstone Formation Around 645 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

See sampled routes

Peak Cadair Idris Minffordd105–844 m samplesMudstone · Felsic tuff · Mudstone and siltstone · Tuff and lava · Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock

Peak Cadair Idris Pony Path162–844 m samplesMicrogranite · Basalt · Mudstone · Tuff and lava · Tuff and lava

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

Friday 4 September 2026Medium confidence

Overall hill weather38/100Poor

Wind30 mph W Gusts42 mph Feels4°C Rain2.0 mm Cloud-free summit45% Cloud base through day900–1,200 m Freezing levelAbove summit Daylight06:30–19:57 · 13.4 h

Forecast confidence: Cloud height is close to summit level at times, so small local changes could put the top in or out of cloud.

Severe spate risk

Burns and unbridged crossings may rise quickly. Assess them at the water and turn back if unsure.

Cloud-free timing: Around 30% early, improving to around 50% later.

A grey, cloudy day on Cadair Idris - Penygadair: summit wind broadly 20-35 mph, with gusts 35-45 mph during the morning (gale-force winds). Severe spate risk based on forecast rainfall. Burns and unbridged crossings may become unsafe or impassable. Most likely from around 00:00 until around 14:00. Cloud base mostly around 900–1200 m through daylight. The top is likely to drift in and out of cloud, with the best chance of a view from late morning into midday. Cloud height is close to summit level at times, so small local changes could put the top in or out of cloud. Cloud is likely to hang lowest on western slopes; the eastern side should see somewhat higher bases and better breaks. Sunshine is likely to be limited to about 4 hours through breaks in the cloud. Some rain is likely, with around 2-5 mm indicated; timing and local totals remain uncertain. Cloud base is the least certain part of this - it could sit a couple of hundred metres either way, especially where it is close to summit level.

At this mountain

Sunshine and sky

Limited sunny breaks. Any sunshine is likely to come through limited breaks.

Modelled sunshine3.5 h27% of daylight

Early0 h sunshine

Midday1.3 h sunshine

Later1 h sunshine

These are direct modelled sunshine hours during daylight, not the probability of sunshine. Cloud cover and summit cloud are assessed separately in the forecast above. Local hill cloud can still make an individual summit brighter or duller than the surrounding model grid.

Morning · 07:00–13:00Poor

28/100

Afternoon & evening · 13:00–22:00Poor

48/100

Separate hill-weather grades help compare an early start with later conditions; the main daytime forecast above still covers the core walking day.

Overnight · 6 p.m.–9 a.m.Wild campingBetaGusts near 40 mph make meaningful shelter important. 87/100Excellent · 600 m View detailsHide details

Night beginning Friday 4 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. Open-ground gusts may reach about 40 mph; seek meaningful shelter. Peak gusts increase from about 30 mph at 300 m to 40 mph at 900 m. Little overnight rain is expected. From around 900 m upward, pitches may spend part of the night in cloud, bringing persistent damp and poor visibility. The coldest temperature falls from about 9.4°C at 300 m to 6.9°C at 900 m.

Overnight rain0.0 mm Open ground · 600 m19 mph · gusts 34 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 6°C or lower

Elevation reference (open ground)

300 m90/100 · very good

Wind / gust: 16 / 29 mph
Typical / low: 10.4° / 9.4°C · several hours
In cloud: Unlikely
Condensation: Low

600 m87/100 · promising

Wind / gust: 19 / 34 mph
Typical / low: 10.4° / 9.4°C · several hours
In cloud: Unlikely
Condensation: Low

900 m54/100 · mixed

Wind / gust: 22 / 40 mph
Typical / low: 8.0° / 6.9°C · much of the night
In cloud: 50% of night
Condensation: Moderate

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 6°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

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 & scramblingBetaGusts near 40 mph increase the seriousness of exposed ground. 5/100Poor · Very poor View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look very poor (5/100). Some rock may still be damp or drying; polished slabs and vegetated sections could be notably worse. The mapped summit rock is Tuff and lava (Pen y gadair Volcanic Formation). Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery. Representative samples along available mapped routes also include Microgranite, Mudstone and 4 other mapped types, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 40 mph; crosswinds can make exposed ridges substantially more serious. Cloud may also make route-finding and retreat harder.

Rock surfaceDamp or dryingPeak gust42 mphRainPossible · 100%

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 Tuff and lava Pen y gadair Volcanic Formation

Origin: Igneous
Rock family: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Low confidence

View the summit BGS record

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them 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.

Mapped variation

8 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 Tuff and lava Pen y gadair Volcanic Formation Around 844 m Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Microgranite Unnamed Igneous Intrusion, Ordovician 162–676 m samples Seen on Peak Cadair Idris Pony Path

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 Mudstone Ty'r Gawen Mudstone Formation 388–762 m samples Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Felsic tuff Craig Cau Formation 198–286 m samples Seen on Peak Cadair Idris Minffordd

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Basalt Unnamed Igneous Intrusion, Ordovician Around 250 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Mudstone and siltstone Ceiswyn Formation Around 105 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Tuff and lava Llyn y Gafr Volcanic Formation Around 332 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock Ty'r Gawen Mudstone Formation Around 645 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

See sampled routes

Peak Cadair Idris Minffordd105–844 m samplesMudstone · Felsic tuff · Mudstone and siltstone · Tuff and lava · Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock

Peak Cadair Idris Pony Path162–844 m samplesMicrogranite · Basalt · Mudstone · Tuff and lava · Tuff and lava

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

Saturday 5 September 2026Medium confidence

Overall hill weather78/100Good

Wind18 mph W Gusts25 mph Feels3°C Rain0.0 mm Cloud-free summit55% Cloud base through day800–1,300 m Freezing levelAbove summit Daylight06:32–19:55 · 13.4 h

Forecast confidence: Cloud height is close to summit level at times, so small local changes could put the top in or out of cloud.

Cloud-free timing: Around 65% early, falling to around 35% later.

A mixed day on Cadair Idris - Penygadair: summit wind broadly 10-25 mph, with gusts 20-30 mph during the afternoon (fresh and blowy). The ground is likely to be saturated after recent rain. Expect boggy paths and rapid runoff if more rain arrives. Cloud base around 1000–1300 m through the morning, lowering to 800–1100 m by late afternoon. The top is likely to drift in and out of cloud, with the best chance of a view from midday into the afternoon. Cloud height is close to summit level at times, so small local changes could put the top in or out of cloud. about 6 hours of sunshine is indicated, with variable cloud giving brighter and duller spells. Little or no rain expected. Cloud base is the least certain part of this - it could sit a couple of hundred metres either way, especially where it is close to summit level.

At this mountain

Sunshine and sky

Brighter and duller spells. Expect alternating brighter and duller spells.

Modelled sunshine5.5 h43% of daylight

EarlyLess than 1 hour sunshine

Midday2.3 h sunshine

Later2.8 h sunshine

These are direct modelled sunshine hours during daylight, not the probability of sunshine. Cloud cover and summit cloud are assessed separately in the forecast above. Local hill cloud can still make an individual summit brighter or duller than the surrounding model grid.

Morning · 07:00–13:00Good

80/100

Afternoon & evening · 13:00–22:00Good

76/100

Separate hill-weather grades help compare an early start with later conditions; the main daytime forecast above still covers the core walking day.

Overnight · 6 p.m.–9 a.m.Wild campingBetaGusts near 45 mph make meaningful shelter important. 87/100Excellent · 600 m View detailsHide details

Night beginning Saturday 5 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. Open-ground gusts may reach about 45 mph; seek meaningful shelter. Peak gusts increase from about 30 mph at 300 m to 45 mph at 900 m. Little overnight rain is expected. From around 900 m upward, pitches may spend part of the night in cloud, bringing persistent damp and poor visibility. The coldest temperature falls from about 10.7°C at 300 m to 8.8°C at 900 m.

Overnight rain0.0 mm Open ground · 600 m17 mph · gusts 35 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 8°C or lower

Elevation reference (open ground)

300 m89/100 · very good

Wind / gust: 14 / 29 mph
Typical / low: 12.8° / 10.7°C
In cloud: Unlikely
Condensation: Low

600 m87/100 · promising

Wind / gust: 17 / 35 mph
Typical / low: 12.8° / 10.7°C
In cloud: Unlikely
Condensation: Low

900 m54/100 · mixed

Wind / gust: 21 / 44 mph
Typical / low: 11.1° / 8.8°C · several hours
In cloud: 50% of night
Condensation: Moderate

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.

The ground is likely to be very wet after recent rain; expect boggy approaches and choose a durable pitch carefully.

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 after recent rain. 68/100Mixed · Fair View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look fair (68/100). Some rock may still be damp or drying; polished slabs and vegetated sections could be notably worse. The mapped summit rock is Tuff and lava (Pen y gadair Volcanic Formation). Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery. Representative samples along available mapped routes also include Microgranite, Mudstone and 4 other mapped types, so rock character and wet-weather behaviour may change across the mountain. Cloud may also make route-finding and retreat harder.

Rock surfaceDamp or dryingPeak gust25 mphRain0.0 mm

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

Mapped rock across the summit and available routes Tuff and lava Pen y gadair Volcanic Formation

Origin: Igneous
Rock family: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Low confidence

View the summit BGS record

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them 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.

Mapped variation

8 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 Tuff and lava Pen y gadair Volcanic Formation Around 844 m Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Microgranite Unnamed Igneous Intrusion, Ordovician 162–676 m samples Seen on Peak Cadair Idris Pony Path

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 Mudstone Ty'r Gawen Mudstone Formation 388–762 m samples Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Felsic tuff Craig Cau Formation 198–286 m samples Seen on Peak Cadair Idris Minffordd

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Basalt Unnamed Igneous Intrusion, Ordovician Around 250 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Mudstone and siltstone Ceiswyn Formation Around 105 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Tuff and lava Llyn y Gafr Volcanic Formation Around 332 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock Ty'r Gawen Mudstone Formation Around 645 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

See sampled routes

Peak Cadair Idris Minffordd105–844 m samplesMudstone · Felsic tuff · Mudstone and siltstone · Tuff and lava · Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock

Peak Cadair Idris Pony Path162–844 m samplesMicrogranite · Basalt · Mudstone · Tuff and lava · Tuff and lava

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

Sunday 6 September 2026Medium confidence

Overall hill weather72/100Good

Wind32 mph SW Gusts45 mph Feels5°C Rain3.3 mm Cloud-free summit55% Cloud base through day500–1,900 m Freezing levelAbove summit Daylight06:33–19:53 · 13.3 h

Forecast confidence: Forecast models disagree on cloud height and timing.

Spate watch

Burns and unbridged crossings may rise quickly. Assess them at the water and turn back if unsure.

Cloud-free timing: Around 70% early, falling to around 30% later.

A mixed day on Cadair Idris - Penygadair: summit wind broadly 20-35 mph, with gusts 40-50 mph during the morning (gale-force winds). The ground is likely to be wet after recent rain. There could be a spate risk based on forecast rainfall. Burns and unbridged crossings may rise quickly. Most likely from around 17:00 until around 03:00 the following day. Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops. Cloud base around 1600–1900 m around midday, lowering to 500–800 m by late afternoon. The top is likely to drift in and out of cloud, with the best chance of a view from early morning into the afternoon. Cloud is likely to hang lowest on southwestern slopes; the northeastern side should see somewhat higher bases and better breaks. A generally bright day is indicated, with about 12 hours of sunshine. Some rain is likely, with around 2-5 mm indicated; timing and local totals remain uncertain. Confidence moderate (Summit wind could be roughly 26-38 mph, which changes how difficult exposed walking may feel) - walker-height summit wind could reasonably be 26-38 mph, with gusts 36-54 mph. Cloud base is the least certain part of this - it could sit a couple of hundred metres either way, especially where it is close to summit level.

At this mountain

Sunshine and sky

Generally bright. A generally bright day is indicated.

Modelled sunshine12 h92% of daylight

Early2 h sunshine

Midday4 h sunshine

Later4 h sunshine

These are direct modelled sunshine hours during daylight, not the probability of sunshine. Cloud cover and summit cloud are assessed separately in the forecast above. Local hill cloud can still make an individual summit brighter or duller than the surrounding model grid.

Morning · 07:00–13:00Excellent

85/100

Afternoon & evening · 13:00–22:00Mixed

58/100

Separate hill-weather grades help compare an early start with later conditions; the main daytime forecast above still covers the core walking day.

Overnight · 6 p.m.–9 a.m.Wild campingBetaGusts near 40 mph make meaningful shelter important. 49/100Poor · 600 m View detailsHide details

Night beginning Sunday 6 September 2026

Full overnight outlook

Open-hillside camping looks mixed overall around 600 m (49/100). Open-ground gusts may reach about 40 mph; seek meaningful shelter. Peak gusts increase from about 25 mph at 300 m to 40 mph at 900 m. A wet night is likely, with roughly 9.4 mm; pitching is most likely to be affected. From around 600 m upward, pitches may spend part of the night in cloud, with high condensation risk, persistent damp and poor visibility; ventilation will matter. The coldest temperature falls from about 10.2°C at 300 m to 7.8°C at 900 m.

Overnight rain9.4 mm Open ground · 600 m20 mph · gusts 33 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 8°C or lower

Elevation reference (open ground)

300 m49/100 · mixed

Wind / gust: 16 / 27 mph
Typical / low: 11.1° / 10.2°C
In cloud: Unlikely
Condensation: Moderate

600 m49/100 · mixed

Wind / gust: 20 / 33 mph
Typical / low: 10.8° / 10.1°C
In cloud: 38% of night
Condensation: High

900 m49/100 · mixed

Wind / gust: 23 / 39 mph
Typical / low: 8.8° / 7.8°C · much of the night
In cloud: 81% of 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 & scramblingBetaGusts near 45 mph increase the seriousness of exposed ground. 14/100Poor · Very poor View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look very poor (14/100). Rain during the useful part of the day is likely to leave rock wet and more slippery. The mapped summit rock is Tuff and lava (Pen y gadair Volcanic Formation). Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery. Representative samples along available mapped routes also include Microgranite, Mudstone and 4 other mapped types, 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 gust44 mphRain2.2 mm

Main factorsgusts around 45 mphwet rock likely

Mapped rock across the summit and available routes Tuff and lava Pen y gadair Volcanic Formation

Origin: Igneous
Rock family: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Low confidence

View the summit BGS record

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them 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.

Mapped variation

8 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 Tuff and lava Pen y gadair Volcanic Formation Around 844 m Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Microgranite Unnamed Igneous Intrusion, Ordovician 162–676 m samples Seen on Peak Cadair Idris Pony Path

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 Mudstone Ty'r Gawen Mudstone Formation 388–762 m samples Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Felsic tuff Craig Cau Formation 198–286 m samples Seen on Peak Cadair Idris Minffordd

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Basalt Unnamed Igneous Intrusion, Ordovician Around 250 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Mudstone and siltstone Ceiswyn Formation Around 105 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Tuff and lava Llyn y Gafr Volcanic Formation Around 332 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock Ty'r Gawen Mudstone Formation Around 645 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

See sampled routes

Peak Cadair Idris Minffordd105–844 m samplesMudstone · Felsic tuff · Mudstone and siltstone · Tuff and lava · Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock

Peak Cadair Idris Pony Path162–844 m samplesMicrogranite · Basalt · Mudstone · Tuff and lava · Tuff and lava

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

Monday 7 September 2026Medium confidence

Overall hill weather22/100Poor

Wind31 mph SW Gusts43 mph Feels4°C Rain0.6 mm Cloud-free summit45% Cloud base through day800–1,100 m Freezing levelAbove summit Daylight06:35–19:50 · 13.2 h

Forecast confidence: A low thunderstorm risk remains difficult to time precisely.

Thunder risk: low

during the evening. Leave exposed summits and ridges if thunder develops.

Spate watch

Burns and unbridged crossings may rise quickly. Assess them at the water and turn back if unsure.

A grey, cloudy day on Cadair Idris - Penygadair: summit wind broadly 20-35 mph, with gusts 40-50 mph during the evening (gale-force winds). Thunderstorms are possible during the evening. Keep an escape route from exposed ridges and descend if thunder develops. The ground is likely to be wet after recent rain. There could be a spate risk based on forecast rainfall. Burns and unbridged crossings may rise quickly. Most likely from around 00:00 until around 03:00 the following day. Cloud base mostly around 800–1100 m through daylight. Expect the top to stay in cloud for most or all of daylight, with no dependable break. Cloud height is close to summit level at times, so small local changes could put the top in or out of cloud. Cloud is likely to hang lowest on southwestern slopes; the northeastern side should see somewhat higher bases and better breaks. about 9 hours of sunshine is indicated, with variable cloud giving brighter and duller spells. Little or no rain expected. Confidence moderate (forecast models agree on the walking impact of the wind) - walker-height summit wind could reasonably be 22-34 mph, with gusts 31-48 mph. Cloud base is the least certain part of this - it could sit a couple of hundred metres either way, especially where it is close to summit level.

At this mountain

Sunshine and sky

Brighter and duller spells. Expect alternating brighter and duller spells.

Modelled sunshine9.1 h70% of daylight

Early1.3 h sunshine

Midday3.7 h sunshine

Later2.2 h sunshine

These are direct modelled sunshine hours during daylight, not the probability of sunshine. Cloud cover and summit cloud are assessed separately in the forecast above. Local hill cloud can still make an individual summit brighter or duller than the surrounding model grid.

Morning · 07:00–13:00Poor

35/100

Afternoon & evening · 13:00–22:00Poor

10/100

Separate hill-weather grades help compare an early start with later conditions; the main daytime forecast above still covers the core walking day.

Overnight · 6 p.m.–9 a.m.Wild campingBetaThunder risk is around 24%; avoid an exposed pitch if storms develop. 35/100Poor · 600 m View detailsHide details

Night beginning Monday 7 September 2026

Full overnight outlook

Open-hillside camping looks poor overall around 600 m (35/100). A lower pitch near 300 m looks more comfortable; conditions are less suitable by 900 m. Open-ground gusts may reach about 50 mph, making exposed pitches a poor choice. Peak gusts increase from about 35 mph at 300 m to 50 mph at 900 m. A wet night is likely, with roughly 18 mm and rain liable to affect both pitching and packing up. From around 600 m upward, pitches may spend part of the night in cloud, with high condensation risk, persistent damp and poor visibility; ventilation will matter. The coldest temperature falls from about 8.6°C at 300 m to 5.6°C at 900 m. Thunder risk is around 24%, broadly during the evening; avoid exposed ridges and summits and be prepared to descend.

Overnight rain18 mm Open ground · 600 m25 mph · gusts 43 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Elevation reference (open ground)

300 m39/100 · poor

Wind / gust: 21 / 35 mph
Typical / low: 9.5° / 8.6°C · much of the night
In cloud: Unlikely
Condensation: Moderate

600 m35/100 · poor

Wind / gust: 25 / 43 mph
Typical / low: 8.8° / 7.9°C · much of the night
In cloud: 44% of night
Condensation: High

900 m23/100 · poor

Wind / gust: 30 / 50 mph
Typical / low: 6.4° / 5.6°C · much of the night
In cloud: 69% of 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 & scramblingBetaThunder risk is around 24%; exposed scrambling may be a poor choice. 0/100Poor · Very poor View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look very poor (0/100). Rain during the useful part of the day is likely to leave rock wet and more slippery. The mapped summit rock is Tuff and lava (Pen y gadair Volcanic Formation). Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery. Representative samples along available mapped routes also include Microgranite, Mudstone and 4 other mapped types, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 40 mph; crosswinds can make exposed ridges substantially more serious. Cloud may also make route-finding and retreat harder. Thunder risk is around 24%, broadly during the evening. It is a high-consequence uncertainty, so avoid committing to exposed ground if storms develop.

Rock surfaceWet rock likelyPeak gust42 mphRain0.5 mm

Main factorsaround 24% thunder risk on exposed groundgusts around 40 mphwet rock likely

Mapped rock across the summit and available routes Tuff and lava Pen y gadair Volcanic Formation

Origin: Igneous
Rock family: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Low confidence

View the summit BGS record

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them 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.

Mapped variation

8 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 Tuff and lava Pen y gadair Volcanic Formation Around 844 m Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Microgranite Unnamed Igneous Intrusion, Ordovician 162–676 m samples Seen on Peak Cadair Idris Pony Path

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 Mudstone Ty'r Gawen Mudstone Formation 388–762 m samples Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Felsic tuff Craig Cau Formation 198–286 m samples Seen on Peak Cadair Idris Minffordd

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Basalt Unnamed Igneous Intrusion, Ordovician Around 250 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Mudstone and siltstone Ceiswyn Formation Around 105 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Tuff and lava Llyn y Gafr Volcanic Formation Around 332 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock Ty'r Gawen Mudstone Formation Around 645 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

See sampled routes

Peak Cadair Idris Minffordd105–844 m samplesMudstone · Felsic tuff · Mudstone and siltstone · Tuff and lava · Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock

Peak Cadair Idris Pony Path162–844 m samplesMicrogranite · Basalt · Mudstone · Tuff and lava · Tuff and lava

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

Tuesday 8 September 2026Medium confidence

Overall hill weather37/100Poor

Wind30 mph W Gusts41 mph Feels0°C Rain3.7 mm Cloud-free summit45% Cloud base through day700–1,200 m Freezing levelAbove summit Daylight06:37–19:48 · 13.2 h

Forecast confidence: Cloud height is close to summit level at times, so small local changes could put the top in or out of cloud.

Spate watch

Burns and unbridged crossings may rise quickly. Assess them at the water and turn back if unsure.

Cloud-free timing: Around 35% early, improving to around 60% later.

A mixed day on Cadair Idris - Penygadair: summit wind broadly 25-35 mph, with gusts 35-45 mph during the morning (gale-force winds). There could be a spate risk based on forecast rainfall. Burns and unbridged crossings may rise quickly. Most likely from around 00:00 until around 23:00. Cloud base around 700-1000 m in the morning, lifting to 900-1200 m around midday. 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 is close to summit level at times, so small local changes could put the top in or out of cloud. Cloud is likely to hang lowest on western slopes; the eastern side should see somewhat higher bases and better breaks. Very little direct sunshine is indicated; cloud is likely to remain extensive. Some rain is likely, with around 2-5 mm indicated; timing and local totals remain uncertain. Cold on top: air temperature broadly 4 to 8°C, feeling around -2 to 2°C in the wind - wrap up. Cloud base is the least certain part of this - it could sit a couple of hundred metres either way, especially where it is close to summit level.

At this mountain

Sunshine and sky

Extensive cloud. Cloud is likely to remain extensive for much of the day.

Modelled sunshine0 h0% of daylight

Early0 h sunshine

Midday0 h sunshine

Later0 h sunshine

These are direct modelled sunshine hours during daylight, not the probability of sunshine. Cloud cover and summit cloud are assessed separately in the forecast above. Local hill cloud can still make an individual summit brighter or duller than the surrounding model grid.

Morning · 07:00–13:00Poor

23/100

Afternoon & evening · 13:00–22:00Mixed

51/100

Separate hill-weather grades help compare an early start with later conditions; the main daytime forecast above still covers the core walking day.

Overnight · 6 p.m.–9 a.m.Wild campingBetaGusts near 40 mph make meaningful shelter important. 80/100Good · 600 m View detailsHide details

Night beginning Tuesday 8 September 2026

Full overnight outlook

Open-hillside camping looks promising overall around 600 m (80/100). 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 increase from about 30 mph at 300 m to 40 mph at 900 m. A little rain or drizzle may coincide with pitching or packing up. From around 900 m upward, pitches may spend part of the night in cloud, bringing persistent damp and poor visibility. The coldest temperature falls from about 8.1°C at 300 m to 5.5°C at 900 m.

Overnight rain0.9 mm Open ground · 600 m22 mph · gusts 34 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Elevation reference (open ground)

300 m82/100 · promising

Wind / gust: 18 / 28 mph
Typical / low: 9.0° / 8.1°C · much of the night
In cloud: Unlikely
Condensation: Low

600 m80/100 · promising

Wind / gust: 22 / 34 mph
Typical / low: 8.6° / 7.7°C · much of the night
In cloud: Unlikely
Condensation: Low

900 m68/100 · reasonable

Wind / gust: 25 / 39 mph
Typical / low: 6.2° / 5.5°C · much of the night
In cloud: 25% of 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 & scramblingBetaGusts near 40 mph increase the seriousness of exposed ground. 0/100Poor · Very poor View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look very poor (0/100). Rain during the useful part of the day is likely to leave rock wet and more slippery. The mapped summit rock is Tuff and lava (Pen y gadair Volcanic Formation). Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery. Representative samples along available mapped routes also include Microgranite, Mudstone and 4 other mapped types, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 40 mph; crosswinds can make exposed ridges substantially more serious.

Rock surfaceWet rock likelyPeak gust41 mphRain3.4 mm

Main factorsgusts around 40 mphwet rock likely

Mapped rock across the summit and available routes Tuff and lava Pen y gadair Volcanic Formation

Origin: Igneous
Rock family: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Low confidence

View the summit BGS record

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them 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.

Mapped variation

8 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 Tuff and lava Pen y gadair Volcanic Formation Around 844 m Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Microgranite Unnamed Igneous Intrusion, Ordovician 162–676 m samples Seen on Peak Cadair Idris Pony Path

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 Mudstone Ty'r Gawen Mudstone Formation 388–762 m samples Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Felsic tuff Craig Cau Formation 198–286 m samples Seen on Peak Cadair Idris Minffordd

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Basalt Unnamed Igneous Intrusion, Ordovician Around 250 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Mudstone and siltstone Ceiswyn Formation Around 105 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Tuff and lava Llyn y Gafr Volcanic Formation Around 332 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock Ty'r Gawen Mudstone Formation Around 645 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

See sampled routes

Peak Cadair Idris Minffordd105–844 m samplesMudstone · Felsic tuff · Mudstone and siltstone · Tuff and lava · Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock

Peak Cadair Idris Pony Path162–844 m samplesMicrogranite · Basalt · Mudstone · Tuff and lava · Tuff and lava

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

Wednesday 9 September 2026Medium confidence

Overall hill weather60/100Mixed

Wind24 mph W Gusts33 mph Feels0°C Rain1.2 mm Cloud-free summit55% Cloud base through day700–1,300 m Freezing levelAbove summit Daylight06:38–19:46 · 13.1 h

Forecast confidence: Forecast models disagree materially on rainfall amounts.

Cloud-free timing: Best around midday at about 65%; around 40% early and 45% later.

A mixed day on Cadair Idris - Penygadair: summit wind broadly 15-30 mph, with gusts 30-40 mph early in the morning (strong winds). The ground is likely to be wet after recent rain. Cloud base around 700–1000 m in the morning, lifting to 1000–1300 m around midday and 900–1200 m by late afternoon. The top is likely to drift in and out of cloud; views may come and go. Cloud height is close to summit level at times, so small local changes could put the top in or out of cloud. Cloud is likely to hang lowest on western slopes; the eastern side should see somewhat higher bases and better breaks. A generally bright day is indicated, with about 12 hours of sunshine. Some rain is likely, with up to around 2 mm indicated; timing and local totals remain uncertain. Cold on top: air temperature broadly 4 to 8°C, feeling around -2 to 2°C in the wind - wrap up. Confidence moderate (Summit wind could be roughly 18-31 mph, which changes how difficult exposed walking may feel) - walker-height summit wind could reasonably be 18-31 mph, with gusts 26-43 mph. Cloud base is the least certain part of this - it could sit a couple of hundred metres either way, especially where it is close to summit level.

At this mountain

Sunshine and sky

Generally bright. A generally bright day is indicated.

Modelled sunshine12 h92% of daylight

Early2 h sunshine

Midday4 h sunshine

Later4 h sunshine

These are direct modelled sunshine hours during daylight, not the probability of sunshine. Cloud cover and summit cloud are assessed separately in the forecast above. Local hill cloud can still make an individual summit brighter or duller than the surrounding model grid.

Morning · 07:00–13:00Mixed

57/100

Afternoon & evening · 13:00–22:00Mixed

63/100

Separate hill-weather grades help compare an early start with later conditions; the main daytime forecast above still covers the core walking day.

Overnight · 6 p.m.–9 a.m.Wild campingBetaAbout 3.4 mm is forecast, with rain liable to affect both pitching and packing up. 64/100Mixed · 600 m View detailsHide details

Night beginning Wednesday 9 September 2026

Full overnight outlook

Open-hillside camping looks reasonable overall around 600 m (64/100). 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 increase from about 20 mph at 300 m to 25 mph at 900 m. Around 3.4 mm is forecast, with rain liable to affect both pitching and packing up. From around 900 m upward, pitches may spend part of the night in cloud, with high condensation risk, persistent damp and poor visibility; ventilation will matter. The coldest temperature falls from about 7.8°C at 300 m to 5.9°C at 900 m.

Overnight rain3.4 mm Open ground · 600 m14 mph · gusts 23 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Elevation reference (open ground)

300 m70/100 · reasonable

Wind / gust: 12 / 19 mph
Typical / low: 9.3° / 7.8°C · much of the night
In cloud: Unlikely
Condensation: Moderate

600 m64/100 · reasonable

Wind / gust: 14 / 23 mph
Typical / low: 8.7° / 7.8°C · much of the night
In cloud: 19% of night
Condensation: High

900 m54/100 · mixed

Wind / gust: 17 / 27 mph
Typical / low: 6.6° / 5.9°C · much of the night
In cloud: 94% of 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 & scramblingBetaGusts near 30 mph increase the seriousness of exposed ground. 36/100Poor · Poor View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look poor (36/100). Rain during the useful part of the day is likely to leave rock wet and more slippery. The mapped summit rock is Tuff and lava (Pen y gadair Volcanic Formation). Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery. Representative samples along available mapped routes also include Microgranite, Mudstone and 4 other mapped types, so rock character and wet-weather behaviour may change across the mountain. Gusts may reach about 30 mph; crosswinds can make exposed ridges substantially more serious.

Rock surfaceWet rock likelyPeak gust32 mphRain1.1 mm

Main factorsgusts around 30 mphwet rock likely

Mapped rock across the summit and available routes Tuff and lava Pen y gadair Volcanic Formation

Origin: Igneous
Rock family: Volcanic rock
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: Low confidence

View the summit BGS record

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them 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.

Mapped variation

8 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 Tuff and lava Pen y gadair Volcanic Formation Around 844 m Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Microgranite Unnamed Igneous Intrusion, Ordovician 162–676 m samples Seen on Peak Cadair Idris Pony Path

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 Mudstone Ty'r Gawen Mudstone Formation 388–762 m samples Seen on Peak Cadair Idris Minffordd, Peak Cadair Idris Pony Path

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Felsic tuff Craig Cau Formation 198–286 m samples Seen on Peak Cadair Idris Minffordd

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Basalt Unnamed Igneous Intrusion, Ordovician Around 250 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Mudstone and siltstone Ceiswyn Formation Around 105 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

Route sample Tuff and lava Llyn y Gafr Volcanic Formation Around 332 m Seen on Peak Cadair Idris Pony Path

Often grippy when dry, but volcanic rocks vary widely; wet lichen, smooth holds and local seepage can still make them slippery.

BGS record

Route sample Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock Ty'r Gawen Mudstone Formation Around 645 m Seen on Peak Cadair Idris Minffordd

Often positive when dry, but smooth, polished or slabby sections can become markedly more slippery when damp.

BGS record

See sampled routes

Peak Cadair Idris Minffordd105–844 m samplesMudstone · Felsic tuff · Mudstone and siltstone · Tuff and lava · Tuffaceous-mudstone with clasts of pillowed basalt and volcaniclastic rock

Peak Cadair Idris Pony Path162–844 m samplesMicrogranite · Basalt · Mudstone · Tuff and lava · Tuff and lava

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

Cadair Idris - Penygadair (Cader Idris) weather forecast.

Today on Cadair Idris - Penygadair.

Seven-day Cadair Idris - Penygadair forecast.

Full overnight outlook

Elevation reference (open ground)

Full climbing & scrambling outlook

8 rock types appear across the available route samples

Full overnight outlook

Elevation reference (open ground)

Full climbing & scrambling outlook

8 rock types appear across the available route samples

Full overnight outlook

Elevation reference (open ground)

Full climbing & scrambling outlook

8 rock types appear across the available route samples

Full overnight outlook

Elevation reference (open ground)

Full climbing & scrambling outlook

8 rock types appear across the available route samples

Full overnight outlook

Elevation reference (open ground)

Full climbing & scrambling outlook

8 rock types appear across the available route samples

Full overnight outlook

Elevation reference (open ground)

Full climbing & scrambling outlook

8 rock types appear across the available route samples

Full overnight outlook

Elevation reference (open ground)

Full climbing & scrambling outlook

8 rock types appear across the available route samples

Stay close to Cadair Idris - Penygadair.

Our cottage shortlist.

Erw Goed Hen Feudy

Croesor Bach

Arthfan

Search exact availability.

Weather around Cadair Idris - Penygadair.

A forecast is part of the decision.