Pen Pumlumon Llygad-bychan Weather Forecast – 727m, Mid Wales and Cambrian Mountains

Monday 21 September 2026Confidence: Medium

Overall hill weather69/100Mixed

Wind5-15 mph westerly Gusts10-20 mph Feels like4 to 8°C PrecipitationUp to around 2 mm Cloud-free summit estimate50% Cloud base through day600-1,200 m Freezing levelAbove summit DaylightSunrise 06:58 · Sunset 19:16 · 12.3 hours daylight

The day on the hill

Frequent summit cloud on Pen Pumlumon Llygad-bychan: summit wind broadly 5-15 mph, with gusts 10-20 mph at times (light winds).

Cloud & views

Cloud base around 900–1200 m in the morning, lowering to 700–1000 m around midday and 600–900 m by late afternoon. Cloud is likely to cover the top for much of the day, though a brief clearance is possible early in the morning.

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

Any sunshine may be confined to lower ground or breaks away from the summit. Drizzle is forecast at times.

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

Forecast confidence

Cloud height remains uncertain, especially where it is close to summit level. 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 70% early, falling to around 45% later.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 1.2 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 1.2 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 Good Summit winds around 5-15 mph. Gusts around 10-20 mph are possible on exposed ground. Summit cloud becomes more persistent later.

73/100

Afternoon · 12:00–17:00 Mixed Summit winds around 5-15 mph. Gusts around 10-20 mph are possible on exposed ground. Rain is forecast during this period.

65/100

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

Overnight · 17:00–08:00Wild campingBetaAbout 1.4 mm is forecast, with rain possible around pitching time. 64/100Mixed · 600 m View detailsHide details

Night beginning Monday 21 September 2026

Full overnight outlook

Open-hillside camping looks reasonable overall around 600 m (64/100). Light winds are expected on open ground, though local shelter and exposure still matter. Around 1.4 mm is forecast, including rain around pitching time. Condensation risk is high near 300 and 600 m, so a wet pack-up is possible. Ventilation will matter.

Overnight rain1.4 mm Open ground · 600 m10 mph · gusts 17 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 10°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 78%
Moonrise: 17:35 BST
Moonset: 01:33 next morning BST

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

Overnight window: 21 Sep, 17:00 BST to 22 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m64/100 · reasonable

Wind / gust: 9 mph / 14 mph
Typical / low: 12.4°C / 12.0°C
In cloud: 0% of modelled night
Condensation: High

600 m64/100 · reasonable

Wind / gust: 10 mph / 17 mph
Typical / low: 12.4°C / 12.0°C
In cloud: 0% of modelled night
Condensation: High

Warmth planning: As a broad starting point, consider a 2-season bag with an ISO/EN comfort rating at or below about 10°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

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

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

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Poor29/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look poor (29/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Slumped mudstone, slumped siltstone and slumped sandstone (Drosgol Formation). Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Cloud may also make route-finding and retreat harder.

Rock surfaceWet rock likelyPeak gust17 mphRain0.7 mm

Main factorswet rock likelymuch of the route may be in cloud

Mapped summit rock Slumped mudstone, slumped siltstone and slumped sandstone Drosgol Formation

Origin: Sedimentary
Rock family: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: High confidence

View the summit BGS record

Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Summit-point bedrock mapping; the actual route may cross different rock, superficial deposits, polish, lichen or seepage.

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

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

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

After dark: aurora and stargazing

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

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

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

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

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

This is about Pen Pumlumon Llygad-bychan on Monday 21 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Tuesday 22 September 2026Confidence: Medium

Overall hill weather68/100Mixed

Wind5-15 mph westerly Gusts10-20 mph Feels like8 to 12°C PrecipitationUp to around 2 mm Cloud-free summit estimate55% Cloud base through day600-1,400 m Freezing levelAbove summit DaylightSunrise 07:00 · Sunset 19:14 · 12.2 hours daylight

The day on the hill

Frequent summit cloud on Pen Pumlumon Llygad-bychan: summit wind broadly 5-15 mph, with gusts 10-20 mph at times (light winds).

Cloud & views

Cloud base around 900–1200 m in the morning, then around 600–900 m around midday and 1100–1400 m by late afternoon. The top is likely to drift in and out of cloud, with the best chance of a view during the evening.

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

Sunny spells are possible away from summit cloud, but may not reach the top while it is in cloud. Drizzle is forecast at times.

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

Forecast confidence

Cloud height remains uncertain, especially where it is close to summit level. Cloud-height uncertainty could put the summit in or out of cloud, even where forecasts agree on the wider cloud cover.

Cloud-free timing: Cloudier around midday at about 45%, compared with around 60% early and 65% later.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 1.6 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.

Early: 0.9 h
Midday: Less than 1 hour
Later: 0 h

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

Morning · 08:00–12:00 Good Summit winds around 5-15 mph. Gusts around 10-20 mph are possible on exposed ground. Summit cloud becomes more persistent later.

73/100

Afternoon · 12:00–17:00 Mixed Summit winds around 0-10 mph. Gusts around 5-15 mph are possible on exposed ground. Rain is forecast during this period.

64/100

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

Overnight · 17:00–08:00Wild campingBetaCondensation risk is high near 300 and 600 m. 64/100Mixed · 600 m View detailsHide details

Night beginning Tuesday 22 September 2026

Full overnight outlook

Open-hillside camping looks reasonable overall around 600 m (64/100). Light winds are expected on open ground, though local shelter and exposure still matter. Little overnight rain is forecast. Condensation risk is high near 300 and 600 m, so a wet pack-up is possible. Ventilation will matter.

Overnight rain0.1 mm Open ground · 600 m8 mph · gusts 18 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 8°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 86%
Moonrise: 17:53 BST
Moonset: 02:50 next morning BST

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

Overnight window: 22 Sep, 17:00 BST to 23 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m64/100 · reasonable

Wind / gust: 7 mph / 15 mph
Typical / low: 12.7°C / 11.5°C
In cloud: 0% of modelled night
Condensation: High

600 m64/100 · reasonable

Wind / gust: 8 mph / 18 mph
Typical / low: 12.7°C / 11.5°C
In cloud: 0% of modelled night
Condensation: High

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

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

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

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Poor43/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look mixed (43/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Slumped mudstone, slumped siltstone and slumped sandstone (Drosgol Formation). Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Cloud may also make route-finding and retreat harder.

Rock surfaceWet rock likelyPeak gust17 mphRain0.8 mm

Main factorswet rock likelymuch of the route may be in cloud

Mapped summit rock Slumped mudstone, slumped siltstone and slumped sandstone Drosgol Formation

Origin: Sedimentary
Rock family: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: High confidence

View the summit BGS record

Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Summit-point bedrock mapping; the actual route may cross different rock, superficial deposits, polish, lichen or seepage.

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

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

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

After dark: aurora and stargazing

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

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

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

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

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

This is about Pen Pumlumon Llygad-bychan on Tuesday 22 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Wednesday 23 September 2026Confidence: Medium

Overall hill weather43/100Poor

Wind10-20 mph northwesterly Gusts20-30 mph Feels like2 to 6°C PrecipitationAround 5-10 mm Cloud-free summit estimate55% Cloud base through day600-1,300 m Freezing levelAbove summit DaylightSunrise 07:01 · Sunset 19:12 · 12.2 hours daylight

The day on the hill

On Pen Pumlumon Llygad-bychan: summit wind broadly 10-20 mph, with gusts 20-30 mph at times (a moderate breeze).

Things to watch

Thunderstorms are possible from the morning into the afternoon. Avoid committing to exposed ridges if storms begin to build.

If a thunderstorm develops, sudden gusts and heavy rain can change conditions quickly. Visibility may drop briefly in showers.

Cloud & views

Cloud base around 600–900 m through the morning, lifting to 1000–1300 m by late afternoon. The top is likely to drift in and out of cloud, with the best chance of a view from late afternoon into the evening.

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

Cloud may hang lower on northwestern slopes and lift somewhat on the southeastern side, but local terrain can differ. Sunny spells are possible away from summit cloud, but may not reach the top while it is in cloud.

Drizzle is forecast at times, with some passing showers too. The forecast total is around 5-10 mm, but local amounts will vary.

Forecast confidence

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

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

Keep a dry warm layer protected. Thunderstorm timing is inherently uncertain and may shift by several hours.

Cloud-free timing: Around 35% early, improving to around 90% 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.

Early: 0 h
Midday: 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 10-20 mph. Gusts around 20-30 mph are possible on exposed ground. Rain is forecast during this period.

32/100

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

54/100

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

Overnight · 17:00–08:00Wild campingBetaConditions look very good, but forecast uncertainty caps the grade at 92/100. 92/100Excellent · 600 m View detailsHide details

Night beginning Wednesday 23 September 2026

Full overnight outlook

Open-hillside camping looks very good overall around 600 m (92/100). Light winds are expected on open ground, though local shelter and exposure still matter. Little overnight rain is forecast. The night is still forecast day 4, so uncertainty keeps it below the exceptional band. The grade is capped at 92/100.

Overnight rain0.0 mm Open ground · 600 m9 mph · gusts 19 mph Morning pack-upNo wet signal Sleeping-bag warmthISO comfort rating about 6°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 92%
Moonrise: 18:08 BST
Moonset: 04:08 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 m92/100 · very good

Wind / gust: 8 mph / 16 mph
Typical / low: 8.6°C / 8.3°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m92/100 · very good

Wind / gust: 9 mph / 19 mph
Typical / low: 8.6°C / 8.3°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 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 & scramblingBetaModerate thunderstorm risk. Avoid exposed rock if storms develop. Wet rock is likely. Poor15/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look very poor (15/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Slumped mudstone, slumped siltstone and slumped sandstone (Drosgol Formation). Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Cloud may also make route-finding and retreat harder. Moderate thunderstorm risk, broadly from the morning into the afternoon. Avoid committing to exposed ground if storms develop.

Rock surfaceWet rock likelyPeak gust23 mphRain5.0 mm

Main factorsmoderate thunderstorm risk on exposed groundwet rock likelymuch of the route may be in cloud

Mapped summit rock Slumped mudstone, slumped siltstone and slumped sandstone Drosgol Formation

Origin: Sedimentary
Rock family: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: High confidence

View the summit BGS record

Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Summit-point bedrock mapping; the actual route may cross different rock, superficial deposits, polish, lichen or seepage.

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

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

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

After dark: aurora and stargazing

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

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

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

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

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

This is about Pen Pumlumon Llygad-bychan on Wednesday 23 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Thursday 24 September 2026Confidence: High

Overall hill weather89/100Excellent

Possible inversionLow confidence · Early morning

Wind10-25 mph southerly Gusts20-30 mph Feels like-2 to 2°C PrecipitationLittle or none Cloud-free summit estimate95% Freezing levelAbove summit DaylightSunrise 07:03 · Sunset 19:09 · 12.1 hours daylight

The day on the hill

Little rain and limited summit cloud on Pen Pumlumon Llygad-bychan: summit wind broadly 10-25 mph, with gusts 20-30 mph at times (a fresh breeze).

Cloud & views

Cloud base around 1000–1300 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.

Rain & temperature

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

A windproof layer will help, with an extra warm layer for stops.

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: 4 h
Later: 3 h

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

Morning · 08:00–12:00 Excellent Summit winds around 5-15 mph. Gusts around 15-25 mph are possible on exposed ground.

90/100

Afternoon · 12:00–17:00 Excellent Summit winds around 10-20 mph. Gusts around 15-25 mph are possible on exposed ground.

88/100

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 Thursday 24 September 2026

Full overnight outlook

Open-hillside camping looks mixed overall around 600 m (59/100). Open-ground gusts may reach about 35 mph. Seek meaningful shelter. Peak gusts range from about 30 mph at 300 m to 35 mph at 600 m. A little rain may coincide with pitching or packing up. Pitches near 600 m may spend part of the night in cloud, bringing damp conditions and poor visibility while cloud is present. Condensation risk is high near 600 m. Ventilation will matter.

Overnight rain0.3 mm Open ground · 600 m21 mph · gusts 33 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 8°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 97%
Moonrise: 18:19 BST
Moonset: 05:27 next morning BST

Extensive cloud may limit moonlight. 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 m59/100 · mixed

Wind / gust: 17 mph / 28 mph
Typical / low: 11.8°C / 11.3°C
In cloud: 0% of modelled night
Condensation: Moderate

600 m59/100 · mixed

Wind / gust: 21 mph / 33 mph
Typical / low: 11.8°C / 11.3°C
In cloud: 47% of modelled night
Condensation: High

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

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

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

Daytime · exposed rockClimbing & scramblingBetaRock may be damp or still drying. Good70/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look fair (70/100). Some rock may still be damp or drying, especially on polished slabs and vegetated sections. The mapped summit rock is Slumped mudstone, slumped siltstone and slumped sandstone (Drosgol Formation). Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully.

Rock surfaceDamp or dryingPeak gust25 mphRain0.0 mm

Main concerndamp or incompletely dried rock possible

Mapped summit rock Slumped mudstone, slumped siltstone and slumped sandstone Drosgol Formation

Origin: Sedimentary
Rock family: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: High confidence

View the summit BGS record

Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Summit-point bedrock mapping; the actual route may cross different rock, superficial deposits, polish, lichen or seepage.

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

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

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

After dark: aurora and stargazing

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

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

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

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

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

This is about Pen Pumlumon Llygad-bychan on Thursday 24 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Friday 25 September 2026Confidence: Medium

Overall hill weather50/100Mixed

Wind10-25 mph westerly Gusts25-35 mph Feels like2 to 6°C PrecipitationAround 2-5 mm Cloud-free summit estimate50% Cloud base through day500-1,800 m Freezing levelAbove summit DaylightSunrise 07:05 · Sunset 19:07 · 12.0 hours daylight

The day on the hill

A wet day with extensive summit cloud on Pen Pumlumon Llygad-bychan: summit wind broadly 10-25 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 through the morning, lifting to 1500–1800 m by late afternoon. The top is likely to drift in and out of cloud, with the best chance of a view from late afternoon into the evening.

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

Cloud may hang lower on western slopes and lift somewhat on the eastern side, but local terrain can differ. Sunny spells are possible away from summit cloud, but may not reach the top while it is in cloud.

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

Forecast models differ on summit wind strength: around 16-37 mph at walker height, with gusts 23-51 mph.

Forecast confidence

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

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

Keep a dry warm layer protected. Summit wind could be roughly 16-37 mph, which changes how difficult exposed walking may feel.

Cloud-free timing: Around 30% early, improving to around 80% later.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 2.8 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.

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

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

Morning · 08:00–12:00 Poor Summit winds around 15-25 mph. Gusts around 25-35 mph are possible on exposed ground. Rain is forecast during this period. Rain is possible during the main walking period, but its timing may shift by several hours.

44/100

Afternoon · 12:00–17:00 Mixed Winds ease compared with the morning. Summit winds around 5-15 mph. Gusts around 10-20 mph are possible on exposed ground. Rain is forecast during this period. Rain is possible during the main walking period, but its timing may shift by several hours.

57/100

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

Overnight · 17:00–08:00Wild campingBetaConditions look very good, but forecast uncertainty caps the grade at 82/100. 82/100Good · 600 m View detailsHide details

Night beginning Friday 25 September 2026

Full overnight outlook

Open-hillside camping looks promising overall around 600 m (82/100). Light winds are expected on open ground, though local shelter and exposure still matter. A little rain may coincide with pitching or packing up. Forecast models are not closely enough agreed for an exceptional grade. The grade is capped at 82/100.

Overnight rain0.8 mm Open ground · 600 m7 mph · gusts 14 mph Morning pack-upNo wet signal Sleeping-bag warmthISO comfort rating about 6°C or lower

Moon overnight

Near-full moon

Illuminated disc: 99%
Moonrise: 18:30 BST
Moonset: 06:46 next morning BST

Extensive cloud may limit moonlight. 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 m82/100 · promising

Wind / gust: 6 mph / 12 mph
Typical / low: 8.6°C / 8.1°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m82/100 · promising

Wind / gust: 7 mph / 14 mph
Typical / low: 8.6°C / 8.1°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

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

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

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

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 30 mph may affect balance on exposed rock. Poor10/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look very poor (10/100). Rain during the climbing period is likely to leave rock wet and more slippery. The mapped summit rock is Slumped mudstone, slumped siltstone and slumped sandstone (Drosgol Formation). Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. 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 gust31 mphRain4.2 mm

Main factorsgusts around 30 mphwet rock likelymuch of the route may be in cloud

Mapped summit rock Slumped mudstone, slumped siltstone and slumped sandstone Drosgol Formation

Origin: Sedimentary
Rock family: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: High confidence

View the summit BGS record

Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Summit-point bedrock mapping; the actual route may cross different rock, superficial deposits, polish, lichen or seepage.

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

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

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

After dark: aurora and stargazing

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

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

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

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

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

This is about Pen Pumlumon Llygad-bychan on Friday 25 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Saturday 26 September 2026Confidence: Unavailable

Overall hill weather82/100Good

Wind5-15 mph southerly Gusts5-15 mph Feels like0 to 4°C PrecipitationLittle or none Cloud-free summit estimate60% Cloud base through day800-1,100 m Freezing levelAbove summit DaylightSunrise 07:06 · Sunset 19:04 · 12.0 hours daylight

The day on the hill

Little rain and limited summit cloud on Pen Pumlumon Llygad-bychan: summit wind broadly 5-15 mph, with gusts 5-15 mph at times (light winds).

Cloud & views

Cloud base mostly around 800–1100 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 uncertainty could put the summit in or out of cloud. Clear spells may be difficult to time.

Sunny spells are possible away from summit cloud, but may not reach the top while it is in cloud.

Rain & temperature

Little or no rain is forecast. Cold on exposed tops: air temperature broadly 2 to 6°C, feeling around 0 to 4°C in the wind.

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

Forecast confidence

Overall confidence is unavailable: insufficient comparable wind, rain guidance.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 11 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

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

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

Morning · 08:00–12:00 Excellent Summit winds around 5-15 mph. Gusts around 5-15 mph are possible on exposed ground. Summit cloud is more persistent early in this period, with better prospects later.

85/100

Afternoon · 12:00–17:00 Good Summit winds around 0-10 mph. Gusts around 5-15 mph are possible on exposed ground. Summit cloud becomes more persistent later.

79/100

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 Saturday 26 September 2026

Full overnight outlook

Open-hillside camping looks mixed overall around 600 m (59/100). Open-ground gusts may reach about 35 mph. Seek meaningful shelter. Peak gusts range from about 30 mph at 300 m to 35 mph at 600 m. Around 1.6 mm is forecast, including rain around pack-up. Pitches near 600 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 and 600 m. Ventilation will matter.

Overnight rain1.6 mm Open ground · 600 m16 mph · gusts 34 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 6°C or lower

Moon overnight

Near-full moon

Illuminated disc: 100%
Moonrise: 18:41 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: 13 mph / 28 mph
Typical / low: 9.8°C / 8.8°C · much of the night
In cloud: 0% of modelled night
Condensation: High

600 m59/100 · mixed

Wind / gust: 16 mph / 34 mph
Typical / low: 9.4°C / 8.8°C · much of the night
In cloud: 40% of modelled night
Condensation: High

Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 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 & scramblingBetaRock may be damp or still drying. Good70/100 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Conditions for exposed scrambling look fair (70/100). Some rock may still be damp or drying, especially on polished slabs and vegetated sections. The mapped summit rock is Slumped mudstone, slumped siltstone and slumped sandstone (Drosgol Formation). Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully.

Rock surfaceDamp or dryingPeak gust12 mphRain0.0 mm

Main concerndamp or incompletely dried rock possible

Mapped summit rock Slumped mudstone, slumped siltstone and slumped sandstone Drosgol Formation

Origin: Sedimentary
Rock family: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: High confidence

View the summit BGS record

Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Summit-point bedrock mapping; the actual route may cross different rock, superficial deposits, polish, lichen or seepage.

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

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

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

After dark: aurora and stargazing

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

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

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

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

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

This is about Pen Pumlumon Llygad-bychan on Saturday 26 September 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Sunday 27 September 2026Confidence: Unavailable

Overall hill weather62/100Mixed

Wind15-30 mph southwesterly Gusts30-40 mph Feels like4 to 8°C PrecipitationAround 2-5 mm Cloud-free summit estimate55% Cloud base through day700-1,000 m Freezing levelAbove summit DaylightSunrise 07:08 · Sunset 19:02 · 11.9 hours daylight

The day on the hill

On Pen Pumlumon Llygad-bychan: summit wind broadly 15-30 mph, with gusts 30-40 mph at times (a fresh breeze).

Cloud & views

Cloud base mostly around 700–1000 m through daylight. The summit is likely to stay mostly clear.

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

Cloud may hang lower on southwestern slopes and lift somewhat on the northeastern side, but local terrain can differ. Drizzle is forecast for much of the day, with some passing showers too.

The forecast total is around 2-5 mm, but local amounts will vary. Forecast models differ on summit wind strength.

Treat the wind figures as a guide.

Forecast confidence

Overall confidence is unavailable: insufficient comparable wind, rain guidance.

Sunshine context Model-grid estimate, not summit sunshine

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

Early: 2 h
Midday: 4 h
Later: 2.9 h

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

Morning · 08:00–12:00 Mixed Summit winds around 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Rain is forecast during this period.

60/100

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.

64/100

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

Overnight · 17:00–08:00Wild campingBetaAbout 1.7 mm is forecast, with rain liable to affect both pitching and packing up. 59/100Mixed · 600 m View detailsHide details

Night beginning Sunday 27 September 2026

Full overnight outlook

Open-hillside camping looks mixed overall around 600 m (59/100). It may be breezy on open ground, with gusts near 30 mph. Around 1.7 mm is forecast, with rain liable to affect both pitching and packing up. Condensation risk is high near 300 and 600 m, so a wet pack-up is possible. Ventilation will matter.

Overnight rain1.7 mm Open ground · 600 m18 mph · gusts 28 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 6°C or lower

Moon overnight

Waning gibbous moon

Illuminated disc: 98%
Moonrise: 18:53 BST
Moonset: Outside this window

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

Overnight window: 27 Sep, 17:00 BST to 28 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m64/100 · reasonable

Wind / gust: 15 mph / 24 mph
Typical / low: 10.1°C / 9.4°C · several hours
In cloud: 0% of modelled night
Condensation: High

600 m59/100 · mixed

Wind / gust: 18 mph / 28 mph
Typical / low: 10.1°C / 9.4°C · several hours
In cloud: 0% of modelled night
Condensation: High

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

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

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

Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Gusts near 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 Slumped mudstone, slumped siltstone and slumped sandstone (Drosgol Formation). Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Gusts may reach about 35 mph. Crosswinds can make exposed ridges substantially more serious.

Rock surfaceWet rock likelyPeak gust33 mphRain2.6 mm

Main factorsgusts around 35 mphwet rock likely

Mapped summit rock Slumped mudstone, slumped siltstone and slumped sandstone Drosgol Formation

Origin: Sedimentary
Rock family: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Rock-response profile: High confidence

View the summit BGS record

Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Summit-point bedrock mapping; the actual route may cross different rock, superficial deposits, polish, lichen or seepage.

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

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

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

After dark: aurora and stargazing

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

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

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

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

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

This is about Pen Pumlumon Llygad-bychan 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

Pen Pumlumon Llygad-bychan weather forecast.

Choose your hill day.

The day on the hill

Cloud & views

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

After dark: aurora and stargazing

The day on the hill

Cloud & views

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

After dark: aurora and stargazing

The day on the hill

Things to watch

Cloud & views

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

After dark: aurora and stargazing

The day on the hill

Cloud & views

Rain & temperature

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

After dark: aurora and stargazing

The day on the hill

Wind & exposure

Cloud & views

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

After dark: aurora and stargazing

The day on the hill

Cloud & views

Rain & temperature

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

After dark: aurora and stargazing

The day on the hill

Cloud & views

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

After dark: aurora and stargazing

Weather around Pen Pumlumon Llygad-bychan.

A forecast is part of the decision.