Pen y Fan Weather Forecast – 886m, Bannau Brycheiniog (Brecon Beacons)

Tuesday 20 October 2026Confidence: Medium

Overall hill weather38Poor

Summit wind · 08:00-17:005-15 mph northeasterly Summit gusts · 08:00-17:0010-20 mph Feels like-2 to 2°C PrecipitationAround 2-5 mm Cloud-free summit estimate40% Cloud base through day400-1,500 m Freezing levelAbove summit DaylightSunrise 07:46 · Sunset 18:10 · 10.4 hours daylight

The day on the hill

A poor day on the tops of Pen y Fan, with drizzle clearing by mid-afternoon and cloud coming and going on the summit.

Wind

On the summit expect light winds of up to 15 mph, mainly north-easterly, with gusts of 10–20 mph at the windiest. It gets windier still after dark, with summit gusts of 20–30 mph, so bear that in mind if you will be out late.

Cloud and visibility

Expect the summit to be in cloud for most of the day. The cloud base could be as low as 400–700 m mid-afternoon. In cloud you'll be finding your way without landmarks, so carry navigation you trust and know how to use, with a backup such as a spare battery or a map and compass. Mist or fog is possible in the valleys early on, clearing by about 6am.

Rain and ground

Drizzle at first, clearing by mid-afternoon. Expect 2–5 mm in total. The timing could shift by a few hours.

Warmth and kit

On the tops it will be around 2 to 6°C, feeling like -2 to 2°C in the wind. The freezing level is above the summits. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 6:10pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

Cloud height is hard to pin down, so the summit could be in or out of cloud at short notice. Things could still change through the day, so keep an eye on the sky.

Sunshine context Model-grid estimate, not summit sunshine

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

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

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

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

29

Afternoon · 12:00–17:00 Poor 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.

46

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

Overnight · 17:00–08:00Wild campingBetaToo windy for an exposed pitch up around 900 m (gusts of about 45 mph). Lower down, a mixed night to camp, mainly because of the wind. 39Poor · 600 m View detailsHide details

Night beginning Tuesday 20 October 2026

Full overnight outlook

Too windy for an exposed pitch up around 900 m. Lower down, a mixed night to camp, mainly because of the wind. Gusts reach about 45 mph around 900 m and nearer 30 mph around 300 m, which makes for a noisy, testing night even in a good tent. Pitch low down and in real shelter, or leave it for another night. The wind swings from westerly to southerly overnight, so a pitch sheltered at dusk may not be by morning. Dry to pitch, then some light rain overnight and into the morning, so expect to pack a wet tent. Above about 600 m you'd likely be in cloud for part of the night: damp, and hard to find your way if you need to move. Overnight lows of about 4°C at 900 m. A 3-season bag rated to about 4°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain2.4 mm Open ground · 600 m18 mph · gusts 36 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 72%
Moonrise: Outside this window
Moonset: 01:46 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: 20 Oct, 17:00 BST to 21 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m59 · mixed

Wind / gust: 15 mph / 30 mph
Typical / low: 8.3°C / 7.5°C · much of the night
In cloud: 0% of modelled night
Condensation: High

600 m39 · poor

Wind / gust: 18 mph / 36 mph
Typical / low: 7.0°C / 6.6°C · much of the night
In cloud: 47% of modelled night
Condensation: High

900 m19 · very poor

Wind / gust: 21 mph / 43 mph
Typical / low: 5.2°C / 4.5°C · a brief spell
In cloud: 47% of modelled night
Condensation: High

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

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

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

Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: wet, slippery rock. Poor0 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceWet rock likelyPeak gust10-20 mphRain3.8 mm

Main factorswet rock likelymuch of the route may be in cloud

Representative rock around the summit and along available routes Sandstone with clay-rich rock Brownstones Formation

Origin: Sedimentary
Broad rock-response group: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Sandstone or gritstone in 100% of 17 BGS samples within 350 m
Rock-response profile: High confidence

View the summit BGS record

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Pen Y Fan Horseshoe

sandstone or gritstone

Generic exposed scrambling terrain; BGS summit-area bedrock samples are 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 darkBetaMostly clear. Moonlight washes out the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-20. All times are UK local time.

Aurora is unlikely on this night

A noticeable aurora display is unlikely here. Any glow may be faint or camera-only. Activity peaks around Kp 4.7 (on a 0 to 9 scale). NOAA has a G1 storm watch out for this date, though the timing of the strongest activity can shift.

Activity can change at short notice. Check again on the night.

Stargazing

Mixed sky conditions during the best available spell: 20 Oct, 23:00 BST to 21 Oct, 00:00 BST.

Mostly clear. Moonlight washes out the fainter stars.

Moon-free dark sky: 21 Oct, 01:45 BST to 05:55 BST.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
20 Oct, 20:00 BST to 21:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
20 Oct, 21:00 BST to 22:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
20 Oct, 22:00 BST to 23:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
20 Oct, 23:00 BST to 21 Oct, 00:00 BST	Mixed sky conditions Mostly clear. Moonlight washes out the fainter stars.
21 Oct, 00:00 BST to 01:00 BST	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
21 Oct, 01:00 BST to 02:00 BST	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
21 Oct, 02:00 BST to 03:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times.
21 Oct, 03:00 BST to 04:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times.
21 Oct, 04:00 BST to 05:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times.
21 Oct, 05:00 BST to 05:55 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times.

Moon, darkness and meteor showers

Gibbous moon, about 72% illuminated.

Moonset around 21 Oct, 01:45 BST.

Full darkness: 20 Oct, 20:00 BST to 21 Oct, 05:55 BST.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 927 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

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

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

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

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

This is about Pen y Fan on Tuesday 20 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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Wednesday 21 October 2026Confidence: Medium

Overall hill weather-8Severe hill conditions

Summit wind · 08:00-17:0010-50 mph northwesterly Summit gusts · 08:00-17:0055-65 mph Feels like-10 to -6°C PrecipitationAround 5-10 mm Cloud-free summit estimate50% Cloud base through day300-900 m Freezing level900-1,200 m DaylightSunrise 07:48 · Sunset 18:07 · 10.3 hours daylight

The day on the hill

A wild day on the tops of Pen y Fan, with very strong, gusty winds and sleet or snow up high. Not a day for the summit.

Wind

On the summit expect a north-westerly wind of 10–50 mph for most of the day, with gusts of 55–65 mph at the windiest. Lower down on the open hillside it will be more like 15–25 mph. Gusts like that are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges.

Cloud and visibility

Cloud on the tops early should lift off them by early afternoon. The cloud base could be as low as 300–600 m early in the morning. Visibility may drop briefly in showers.

Rain and ground

Sleet is possible on the tops, and it could turn to snow if it is a little colder. Rain at first, clearing by mid-afternoon. Expect 5–10 mm in total, measured as melted water, so any snow would lie deeper. Some forecast models keep it drier in the morning.

Warmth and kit

On the tops it will be around 0 to 4°C, feeling like -10 to -6°C in the wind. The freezing level falls through the day, to around 1100–1400 m by mid-morning. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 6:05pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

There is some disagreement between forecast models on wind strength. Some of the detail could still change, so have a last look at the forecast in the morning before you set off.

Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans. Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans.

Sunshine context Model-grid estimate, not summit sunshine

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

Early: 0 h
Midday: 0.8 h
Later: 2 h

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

Morning · 08:00–12:00 Severe hill conditions Summit winds around 25-35 mph early in the morning, strengthening to 40-50 mph later. Gusts around 55-65 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period. Rain is possible during the morning, but forecast models disagree on whether it will fall.

-14

Afternoon · 12:00–17:00 Severe hill conditions Summit winds around 40-50 mph in the early afternoon, easing to 35-45 mph later. Gusts around 55-65 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period. Rain is possible during the afternoon, but forecast models disagree on whether it will fall.

-2

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

Overnight · 17:00–08:00Wild campingBetaToo windy for an exposed pitch up around 900 m (gusts of about 45 mph). Lower down, a mixed night to camp, mainly because of the wind. 39Poor · 600 m View detailsHide details

Night beginning Wednesday 21 October 2026

Full overnight outlook

Too windy for an exposed pitch up around 900 m. Lower down, a mixed night to camp, mainly because of the wind. Gusts reach about 45 mph around 900 m and nearer 30 mph around 300 m, enough to damage a tent on open ground. Pitch low down and in real shelter, or leave it for another night. Dry to pitch, then a little rain overnight, easing by morning, though the tent may still be wet. A cold night, down to about 1°C around 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain0.6 mm Open ground · 600 m13 mph · gusts 38 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 80%
Moonrise: Outside this window
Moonset: 03:02 next morning BST

Views of the Moon may come and go through cloud breaks. Illumination describes the sunlit part of the Moon, not brightness at your pitch.

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

Elevation reference (open ground)

300 m59 · mixed

Wind / gust: 11 mph / 32 mph
Typical / low: 5.6°C / 4.9°C · a brief spell
In cloud: 0% of modelled night
Condensation: Low

600 m39 · poor

Wind / gust: 13 mph / 38 mph
Typical / low: 5.0°C / 4.3°C · several hours
In cloud: 0% of modelled night
Condensation: Low

900 m19 · very poor

Wind / gust: 17 mph / 45 mph
Typical / low: 2.2°C / 0.7°C · much of the night
In cloud: 20% of modelled night
Condensation: Moderate

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

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

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

Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 55–65 mph. Poor0 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 55–65 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceWet rock likelyPeak gust55-65 mphRain8.7 mm

Main factorsgusts of 55–65 mphwet rock likelymuch of the route may be in cloud

Representative rock around the summit and along available routes Sandstone with clay-rich rock Brownstones Formation

Origin: Sedimentary
Broad rock-response group: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Sandstone or gritstone in 100% of 17 BGS samples within 350 m
Rock-response profile: High confidence

View the summit BGS record

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Pen Y Fan Horseshoe

sandstone or gritstone

Generic exposed scrambling terrain; BGS summit-area bedrock samples are 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 darkBetaSome forecasts show clear spells, others keep it cloudy; check again nearer the time. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-21. All times are UK local time.

Aurora is unlikely on this night

A noticeable aurora display is unlikely here. Any glow may be faint or camera-only. Activity peaks around Kp 3.3 (on a 0 to 9 scale).

Activity can change at short notice. Check again on the night.

Stargazing

Good sky conditions during the best available spell: 22 Oct, 05:00 BST to 06:00 BST.

Some forecasts show clear spells, others keep it cloudy; check again nearer the time.

Moon-free dark sky: 22 Oct, 03:00 BST to 06:00 BST.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
21 Oct, 20:00 BST to 21:00 BST	Mixed sky conditions Some breaks in the cloud, so stars at times. Moonlight washes out the fainter stars.
21 Oct, 21:00 BST to 22:00 BST	Mixed sky conditions Some breaks in the cloud, so stars at times. Moonlight washes out the fainter stars.
21 Oct, 22:00 BST to 23:00 BST	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
21 Oct, 23:00 BST to 22 Oct, 00:00 BST	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
22 Oct, 00:00 BST to 01:00 BST	Poor sky conditions Some breaks in the cloud, so stars at times. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
22 Oct, 01:00 BST to 02:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
22 Oct, 02:00 BST to 03:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.
22 Oct, 03:00 BST to 04:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
22 Oct, 04:00 BST to 05:00 BST	Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
22 Oct, 05:00 BST to 06:00 BST	Good sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.

Moon, darkness and meteor showers

Gibbous moon, about 80% illuminated.

Moonset around 22 Oct, 03:00 BST.

Full darkness: 21 Oct, 20:00 BST to 22 Oct, 06:00 BST.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 927 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

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

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

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

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

This is about Pen y Fan on Wednesday 21 October 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 22 October 2026Confidence: Medium

Overall hill weather82Good

Summit wind · 08:00-17:005-20 mph southwesterly Summit gusts · 08:00-17:0015-25 mph Feels like-6 to -2°C PrecipitationLittle or none Cloud-free summit estimate90% Freezing level700-1,000 m DaylightSunrise 07:49 · Sunset 18:05 · 10.3 hours daylight

The day on the hill

A good day on Pen y Fan, though expect burns rising after rain.

Things to watch

Burns could rise quickly from the evening into the night. Timings are rough. Turn back if a crossing looks unsafe.

Wind

On the summit expect a south-westerly wind of 5–20 mph for most of the day, with gusts of 15–25 mph at the windiest. The wind turns south-westerly in the early afternoon. Lower down on the open hillside the wind will be light, under 10 mph. It gets windier still after dark, with summit gusts of 45–55 mph, so bear that in mind if you will be out late.

Cloud and visibility

The tops should stay clear of cloud all day. The air should be clear too, so expect far-reaching views from the tops.

Rain and ground

Dry through the daylight hours, but rain arrives after dark. Some forecast models bring rain, so don't count on it staying dry. It will be wet underfoot after recent rain.

Warmth and kit

On the tops it will be around 0 to 4°C, feeling like -6 to -2°C in the wind. It turns milder through the day. The freezing level is close to summit height. Take a hat, gloves, a windproof and a spare warm layer.

Daylight

Sunset is around 6:05pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

It's still two days off and could change, so check again nearer the time.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 8 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 2 h
Midday: 4 h
Later: 0 h

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

Morning · 08:00–12:00 Excellent Summit winds around 10-20 mph. Gusts around 15-25 mph are possible on exposed ground. Rain is possible during the main walking period, but its timing may shift by several hours.

90

Afternoon · 12:00–17:00 Good Summit winds around 5-15 mph. Gusts around 10-20 mph are possible on exposed ground. Some forecast models bring rain during the afternoon, while others keep it mostly dry. Rain is possible during the main walking period, but its timing may shift by several hours.

73

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

Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 60 mph and heavy rain, around 20 mm. 9Poor · 600 m View detailsHide details

Night beginning Thursday 22 October 2026

Full overnight outlook

Not a night to camp on the open hill. Gusts reach about 60 mph around 900 m and nearer 40 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. The wind swings from southerly to northwesterly overnight, so a pitch sheltered at dusk may not be by morning. Expect heavy rain, around 20 mm, with rain while you pitch and still falling when you pack up. Above about 600 m you'd likely be in cloud for part of the night: damp, and hard to find your way if you need to move. Overnight lows of about 4°C at 900 m. A 3-season bag rated to about 4°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain22.3 mm Open ground · 600 m27 mph · gusts 49 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 88%
Moonrise: Outside this window
Moonset: 04:20 next morning BST

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

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

Elevation reference (open ground)

300 m19 · very poor

Wind / gust: 23 mph / 41 mph
Typical / low: 8.7°C / 7.4°C · much of the night
In cloud: 0% of modelled night
Condensation: Moderate

600 m9 · very poor

Wind / gust: 27 mph / 49 mph
Typical / low: 7.0°C / 5.4°C · much of the night
In cloud: 27% of modelled night
Condensation: High

900 m9 · very poor

Wind / gust: 32 mph / 58 mph
Typical / low: 5.1°C / 3.7°C · several hours
In cloud: 47% of modelled night
Condensation: High

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

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

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

Daytime · exposed rockClimbing & scramblingBetaPoor conditions for exposed scrambling. Poor35 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Poor conditions for exposed scrambling. After recent rain the rock may still be wet in places, especially shaded holds and drainage lines. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceDry overhead; seepage uncertainPeak gust15-25 mphRainPossible · 100%

Main concerndamp or incompletely dried rock possible

Representative rock around the summit and along available routes Sandstone with clay-rich rock Brownstones Formation

Origin: Sedimentary
Broad rock-response group: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Sandstone or gritstone in 100% of 17 BGS samples within 350 m
Rock-response profile: High confidence

View the summit BGS record

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Pen Y Fan Horseshoe

sandstone or gritstone

Generic exposed scrambling terrain; BGS summit-area bedrock samples are 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 darkBetaMostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-22. All times are UK local time.

Aurora is unlikely on this night

Too quiet for a likely sighting from here. Activity peaks around Kp 2.7 (on a 0 to 9 scale). It would take about Kp 6.3 for a camera to pick up a glow low in the north, though that is not a hard line.

Activity can change at short notice. Check again on the night.

Stargazing

Poor sky conditions during the best available spell: 22 Oct, 20:00 BST to 21:00 BST.

Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.

Moon-free dark sky: 23 Oct, 04:15 BST to 06:00 BST.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
22 Oct, 20:00 BST to 21:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
22 Oct, 21:00 BST to 22:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
22 Oct, 22:00 BST to 23:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
22 Oct, 23:00 BST to 23 Oct, 00:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
23 Oct, 00:00 BST to 01:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
23 Oct, 01:00 BST to 02:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
23 Oct, 02:00 BST to 03:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
23 Oct, 03:00 BST to 04:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.
23 Oct, 04:00 BST to 05:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.
23 Oct, 05:00 BST to 06:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.

Moon, darkness and meteor showers

Gibbous moon, about 88% illuminated.

Moonset around 23 Oct, 04:15 BST.

Full darkness: 22 Oct, 20:00 BST to 23 Oct, 06:00 BST.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 927 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

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

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

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

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

This is about Pen y Fan on Thursday 22 October 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 23 October 2026Confidence: Low

Overall hill weather-45Severe hill conditions

Summit wind · 08:00-17:0035-60 mph northwesterly Summit gusts · 08:00-17:0070-80 mph Feels like-10 to -6°C PrecipitationAround 5-10 mm Cloud-free summit estimate50% Cloud base through day600-1,400 m Freezing level800-1,100 m DaylightSunrise 07:51 · Sunset 18:03 · 10.2 hours daylight

The day on the hill

A wild day on the tops of Pen y Fan, with severe winds and burns likely to be in spate. Not a day for the summit.

Things to watch

Burns and rivers are likely to be in spate through much of the day and into the evening, so unbridged crossings could be difficult or impossible. Timings are rough. Turn back if a crossing looks unsafe.

Wind

On the summit expect a north-westerly wind of 35–60 mph for most of the day, with gusts of 70–80 mph at the windiest. Lower down on the open hillside it will be more like 15–25 mph. Gusts like that are strong enough to make movement extremely difficult on exposed ground. During the strongest gusts, walking or standing may be impossible and you could be blown off your feet. Avoid exposed high ground. If the windier forecast models are right, summit gusts could reach 85–95 mph.

Cloud and visibility

Expect the summit to be in cloud for most of the day. The cloud base could be as low as 400–700 m early in the morning. A few forecast models bring it lower still, to around 300–600 m.

Rain and ground

Sleet is possible on the tops, and it could turn to snow if it is a little colder. Rain for much of the day, turning lighter later. Expect 5–10 mm in total, measured as melted water, so any snow would lie deeper. Some forecast models keep it drier in the morning. It will be wet underfoot after recent rain.

Warmth and kit

On the tops it will be around -2 to 2°C, feeling like -10 to -6°C in the wind. The freezing level is close to summit height. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 6:05pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

There is some disagreement between forecast models on wind strength. It's still three days off and could change, so check again nearer the time.

Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans. Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 4.5 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.

Early: 0 h
Midday: 1.5 h
Later: 2 h

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

Morning · 08:00–12:00 Severe hill conditions Summit winds around 40-50 mph early in the morning, strengthening to 50-60 mph later. Gusts around 70-80 mph are possible on exposed ground. Gusts this strong can make movement extremely difficult on exposed ground. During the strongest gusts, walking or standing may be impossible and you could be blown off your feet. Avoid exposed high ground. Rain is forecast during this period. Rain is possible during the morning, but forecast models disagree on whether it will fall.

-41

Afternoon · 12:00–17:00 Severe hill conditions Summit winds around 50-60 mph in the early afternoon, easing to 40-50 mph later. Gusts around 70-80 mph are possible on exposed ground. Gusts this strong can make movement extremely difficult on exposed ground. During the strongest gusts, walking or standing may be impossible and you could be blown off your feet. Avoid exposed high ground. Rain is forecast during this period. Rain is possible during the afternoon, but forecast models disagree on whether it will fall.

-49

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

Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 60 mph. 9Poor · 600 m View detailsHide details

Night beginning Friday 23 October 2026

Full overnight outlook

Not a night to camp on the open hill. Gusts reach about 60 mph around 900 m and nearer 45 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. It should stay dry. A cold night, down to about 1°C around 900 m. A warm 3-season or 3–4 season bag rated to about 0°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain0.2 mm Open ground · 600 m30 mph · gusts 52 mph Morning pack-upNo wet signal Sleeping-bag warmthISO comfort rating about 0°C or lower

Moon overnight

Waxing gibbous moon

Illuminated disc: 94%
Moonrise: Outside this window
Moonset: 05:40 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 Oct, 17:00 BST to 24 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m19 · very poor

Wind / gust: 25 mph / 44 mph
Typical / low: 4.0°C / 3.6°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

600 m9 · very poor

Wind / gust: 30 mph / 52 mph
Typical / low: 3.4°C / 2.9°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

900 m0 · very poor

Wind / gust: 36 mph / 62 mph
Typical / low: 1.1°C / 0.9°C · much of the night
In cloud: 0% of modelled night
Condensation: Low

Warmth planning: As a broad starting point, consider a warm 3-season or 3–4 season bag with an ISO/EN comfort rating at or below about 0°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 & scramblingBetaVery poor conditions for exposed scrambling: gusts of 70–80 mph. Poor0 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 70–80 mph are strong enough to make movement extremely difficult on exposed ground. During the strongest gusts, walking or standing may be impossible and you could be blown off your feet. Avoid exposed high ground. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceWet rock likelyPeak gust70-80 mphRain7.7 mm

Main factorsgusts of 70–80 mphwet rock likelymuch of the route may be in cloud

Representative rock around the summit and along available routes Sandstone with clay-rich rock Brownstones Formation

Origin: Sedimentary
Broad rock-response group: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Sandstone or gritstone in 100% of 17 BGS samples within 350 m
Rock-response profile: High confidence

View the summit BGS record

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Pen Y Fan Horseshoe

sandstone or gritstone

Generic exposed scrambling terrain; BGS summit-area bedrock samples are 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 darkBetaSome breaks in the cloud, so stars at times. Moonlight washes out the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-23. All times are UK local time.

Stargazing

Mixed sky conditions during the best available spell: 23 Oct, 22:00 BST to 23:00 BST.

Some breaks in the cloud, so stars at times. Moonlight washes out the fainter stars.

Moon-free dark sky: 24 Oct, 05:35 BST to 06:00 BST.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
23 Oct, 19:55 BST to 20:00 BST	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
23 Oct, 20:00 BST to 21:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
23 Oct, 21:00 BST to 22:00 BST	Poor sky conditions Some breaks in the cloud, so stars at times. Moonlight washes out the fainter stars.
23 Oct, 22:00 BST to 23:00 BST	Mixed sky conditions Some breaks in the cloud, so stars at times. Moonlight washes out the fainter stars.
23 Oct, 23:00 BST to 24 Oct, 00:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
24 Oct, 00:00 BST to 01:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
24 Oct, 01:00 BST to 02:00 BST	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
24 Oct, 02:00 BST to 03:00 BST	Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree.
24 Oct, 03:00 BST to 04:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
24 Oct, 04:00 BST to 05:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
24 Oct, 05:00 BST to 06:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars.

Moon, darkness and meteor showers

Gibbous moon, about 94% illuminated.

Moonset around 24 Oct, 05:35 BST.

Full darkness: 23 Oct, 19:55 BST to 24 Oct, 06:00 BST.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 927 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

Cross-check, don’t forecast-shop.

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

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

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

How to use more than one mountain forecast

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

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

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

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

This is about Pen y Fan on Friday 23 October 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 24 October 2026Confidence: Medium

Overall hill weather56Mixed

Summit wind · 08:00-17:0015-30 mph southwesterly Summit gusts · 08:00-17:0030-40 mph Feels like-8 to -4°C PrecipitationAround 5-10 mm Cloud-free summit estimate70% Freezing levelAbove summit DaylightSunrise 07:53 · Sunset 18:01 · 10.1 hours daylight

The day on the hill

A mixed day on Pen y Fan, with rain arriving in the early afternoon.

Wind

On the summit expect a south-westerly wind of 15–30 mph for most of the day, with gusts of 30–40 mph at the windiest. The wind turns south-westerly around midday. Lower down on the open hillside it will be more like 5–15 mph. Gusts like that will be noticeable on ridges and open tops, and you will chill quickly when you stop. It gets windier still after dark, with summit gusts of 45–55 mph, so bear that in mind if you will be out late.

Cloud and visibility

The tops should stay clear of cloud all day.

Rain and ground

A band of rain moves in during the early afternoon and becomes heavier through the afternoon. Expect 5–10 mm in total. Totals are uncertain and could be higher. It will be wet underfoot after recent rain.

Warmth and kit

On the tops it will be around 0 to 4°C, feeling like -8 to -4°C in the wind. The freezing level is close to summit height. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 6pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

There is some disagreement between forecast models on wind strength. It's still four days off and could change, so check again nearer the time.

Sunshine context Model-grid estimate, not summit sunshine

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

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

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

Morning · 08:00–12:00 Mixed Summit winds around 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Some forecast models bring rain during the morning, while others keep it mostly dry.

56

Afternoon · 12:00–17:00 Mixed More rain is expected. Summit winds around 15-30 mph. Gusts around 30-40 mph are possible on exposed ground. Rain is forecast during this period. Rain is forecast during the afternoon, but models differ considerably on the amount.

56

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

Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 65 mph and around 9 mm of rain. 9Poor · 600 m View detailsHide details

Night beginning Saturday 24 October 2026

Full overnight outlook

Not a night to camp on the open hill. Gusts reach about 65 mph around 900 m and nearer 50 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. The wind swings from southwesterly to westerly overnight, so a pitch sheltered at dusk may not be by morning. Expect a wet night, around 9 mm of rain, with rain while you pitch and still falling when you pack up. Above about 600 m you'd likely be in cloud for part of the night: damp, and hard to find your way if you need to move. Overnight lows of about 4°C at 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain8.7 mm Open ground · 600 m34 mph · gusts 57 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Near-full moon

Illuminated disc: 98%
Moonrise: Outside this window
Moonset: 06:03 next morning GMT

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

Overnight window: 24 Oct, 17:00 BST to 25 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m9 · very poor

Wind / gust: 28 mph / 48 mph
Typical / low: 12.6°C / 6.7°C · several hours
In cloud: 0% of modelled night
Condensation: Moderate

600 m9 · very poor

Wind / gust: 34 mph / 57 mph
Typical / low: 11.4°C / 5.8°C · several hours
In cloud: 38% of modelled night
Condensation: High

900 m0 · very poor

Wind / gust: 40 mph / 67 mph
Typical / low: 9.3°C / 4.4°C · a brief spell
In cloud: 56% of modelled night
Condensation: High

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

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

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

Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 30–40 mph. Poor0 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 30–40 mph could throw you off balance on exposed moves and ridges. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceWet rock likelyPeak gust30-40 mphRain6.9 mm

Main factorsgusts of 30–40 mphwet rock likely

Representative rock around the summit and along available routes Sandstone with clay-rich rock Brownstones Formation

Origin: Sedimentary
Broad rock-response group: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Sandstone or gritstone in 100% of 17 BGS samples within 350 m
Rock-response profile: High confidence

View the summit BGS record

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Pen Y Fan Horseshoe

sandstone or gritstone

Generic exposed scrambling terrain; BGS summit-area bedrock samples are 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 darkBetaMostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-24. All times are UK local time.

Aurora outlook

Nothing notable expected.

A broad activity outlook, not a forecast of a visible display. Cloud and activity can change before the night.

Stargazing

Poor sky conditions during the best available spell: 25 Oct, 04:00 GMT to 05:00 GMT.

Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.

A bright moon is up all through the dark hours, washing out fainter stars and meteors.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
24 Oct, 19:55 BST to 20:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
24 Oct, 20:00 BST to 21:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
24 Oct, 21:00 BST to 22:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
24 Oct, 22:00 BST to 23:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
24 Oct, 23:00 BST to 25 Oct, 00:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
25 Oct, 00:00 BST to 01:00 BST	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
25 Oct, 01:00 GMT to 02:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
25 Oct, 01:00 BST to 01:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
25 Oct, 02:00 GMT to 03:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
25 Oct, 03:00 GMT to 04:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
25 Oct, 04:00 GMT to 05:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars.
25 Oct, 05:00 GMT to 05:05 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars.

Moon, darkness and meteor showers

Near-full moon, about 98% illuminated.

Moonset around 25 Oct, 05:55 GMT.

Full darkness: 24 Oct, 19:55 BST to 25 Oct, 05:05 GMT.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 927 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

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

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

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

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

This is about Pen y Fan on Saturday 24 October 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 25 October 2026Confidence: Unavailable

Overall hill weather-5Severe hill conditions

Summit wind · 08:00-17:0045-60 mph westerly Summit gusts · 08:00-17:0065-75 mph Feels like-4 to 0°C PrecipitationAround 5-10 mm Cloud-free summit estimate65% Cloud base through day900-1,500 m Freezing levelAbove summit DaylightSunrise 06:55 · Sunset 16:59 · 10.1 hours daylight

The day on the hill

A wild day on the tops of Pen y Fan, with severe winds and rain for much of the day. Not a day for the summit.

Wind

On the summit expect a westerly wind of 45–60 mph for most of the day, with gusts of 65–75 mph at the windiest. Lower down on the open hillside it will be more like 15–25 mph. Gusts like that are strong enough to make movement extremely difficult on exposed ground. During the strongest gusts, walking or standing may be impossible and you could be blown off your feet. Avoid exposed high ground. If the windier forecast models are right, summit gusts could reach 95–105 mph.

Cloud and visibility

The tops should stay mostly clear of cloud. A few forecast models bring the cloud base down to around 300–600 m at times. The cloud base sits close to summit height, so the top could go in and out of cloud at short notice.

Rain and ground

Rain for much of the day, turning lighter later. Expect 5–10 mm in total. It will be wet underfoot after recent rain.

Warmth and kit

On the tops it will be around 4 to 8°C, feeling like -4 to 0°C in the wind. It turns colder through the day. The freezing level is above the summits. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 5pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

It's still five days off and could change, so check again nearer the time.

Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans. Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 9.9 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: 3 h
Midday: 4 h
Later: 0.9 h

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

Morning · 08:00–12:00 Severe hill conditions Summit winds around 45-55 mph. Gusts around 65-75 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period.

-8

Afternoon · 12:00–17:00 Severe hill conditions Summit winds around 50-60 mph. Gusts around 65-75 mph are possible on exposed ground. Gusts this strong can make movement extremely difficult on exposed ground. During the strongest gusts, walking or standing may be impossible and you could be blown off your feet. Avoid exposed high ground. Rain is forecast during this period.

-2

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

Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 70 mph. 0Poor · 600 m View detailsHide details

Night beginning Sunday 25 October 2026

Full overnight outlook

Not a night to camp on the open hill. Gusts reach about 70 mph around 900 m and nearer 50 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. Expect some light rain, with rain while you pitch and still falling when you pack up. A cold night, down to about 2°C around 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain2.5 mm Open ground · 600 m30 mph · gusts 61 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 2°C or lower

Moon overnight

Near-full moon

Illuminated disc: 100%
Moonrise: Outside this window
Moonset: 07:31 next morning GMT

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: 25 Oct, 17:00 GMT to 26 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m9 · very poor

Wind / gust: 25 mph / 50 mph
Typical / low: 7.0°C / 4.5°C · several hours
In cloud: 0% of modelled night
Condensation: Low

600 m0 · very poor

Wind / gust: 30 mph / 61 mph
Typical / low: 5.6°C / 4.5°C · several hours
In cloud: 0% of modelled night
Condensation: Low

900 m0 · very poor

Wind / gust: 35 mph / 72 mph
Typical / low: 3.2°C / 1.9°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 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.

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

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

Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 65–75 mph. Poor0 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 65–75 mph are strong enough to make movement extremely difficult on exposed ground. During the strongest gusts, walking or standing may be impossible and you could be blown off your feet. Avoid exposed high ground. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceWet rock likelyPeak gust65-75 mphRain5.0 mm

Main factorsgusts of 65–75 mphwet rock likely

Representative rock around the summit and along available routes Sandstone with clay-rich rock Brownstones Formation

Origin: Sedimentary
Broad rock-response group: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Sandstone or gritstone in 100% of 17 BGS samples within 350 m
Rock-response profile: High confidence

View the summit BGS record

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Pen Y Fan Horseshoe

sandstone or gritstone

Generic exposed scrambling terrain; BGS summit-area bedrock samples are 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 darkBetaMostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-25. All times are UK local time.

Aurora outlook

Nothing notable expected.

A broad activity outlook, not a forecast of a visible display. Cloud and activity can change before the night.

Stargazing

Poor sky conditions during the best available spell: 25 Oct, 19:00 GMT to 20:00 GMT.

Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.

A bright moon is up all through the dark hours, washing out fainter stars and meteors.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
25 Oct, 18:50 GMT to 19:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
25 Oct, 19:00 GMT to 20:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
25 Oct, 20:00 GMT to 21:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
25 Oct, 21:00 GMT to 22:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
25 Oct, 22:00 GMT to 23:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
25 Oct, 23:00 GMT to 26 Oct, 00:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
26 Oct, 00:00 GMT to 01:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 01:00 GMT to 02:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 02:00 GMT to 03:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 03:00 GMT to 04:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 04:00 GMT to 05:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 05:00 GMT to 05:05 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.

Moon, darkness and meteor showers

Near-full moon, about 100% illuminated.

Moonset around 26 Oct, 07:20 GMT.

Full darkness: 25 Oct, 18:50 GMT to 26 Oct, 05:05 GMT.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 927 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

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

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

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

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

This is about Pen y Fan on Sunday 25 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

Open the questions to take part.

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

Monday 26 October 2026Confidence: Unavailable

Overall hill weather66Mixed

Summit wind · 08:00-17:0020-30 mph westerly Summit gusts · 08:00-17:0030-40 mph Feels like-4 to 0°C PrecipitationUp to around 2 mm Cloud-free summit estimate65% Cloud base through day1,000-1,300 m Freezing levelAbove summit DaylightSunrise 06:56 · Sunset 16:57 · 10.0 hours daylight

The day on the hill

A mixed day on Pen y Fan: breezy on the tops.

Wind

On the summit expect a westerly wind of 20–30 mph for most of the day, with gusts of 30–40 mph at the windiest. Lower down on the open hillside it will be more like 5–15 mph. Gusts like that will be noticeable on ridges and open tops, and you will chill quickly when you stop.

Cloud and visibility

The tops should stay mostly clear of cloud. A few forecast models bring the cloud base down to around 600–900 m at times. The cloud base sits close to summit height, so the top could go in and out of cloud at short notice.

Rain and ground

Drizzle at first, clearing by midday. It will be wet underfoot after recent rain.

Warmth and kit

On the tops it will be around 2 to 6°C, feeling like -4 to 0°C in the wind. The freezing level is above the summits. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.

Daylight

Sunset is around 4:55pm, so allow time to get off the hill before dark, and carry a head torch.

Forecast confidence

It's still six days off and could change, so check again nearer the time.

Sunshine context Model-grid estimate, not summit sunshine

The surrounding model grid indicates 4.6 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: 3.1 h
Later: Less than 1 hour

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

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

62

Afternoon · 12:00–17:00 Good Summit winds around 20-30 mph. Gusts around 30-40 mph are possible on exposed ground.

70

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

Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 60 mph and around 12 mm of rain. 9Poor · 600 m View detailsHide details

Night beginning Monday 26 October 2026

Full overnight outlook

Not a night to camp on the open hill. Gusts reach about 60 mph around 900 m and nearer 45 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. Expect a wet night, around 12 mm of rain, with rain while you pitch and still falling when you pack up. Up around 900 m you'd likely be in cloud for part of the night: damp, and hard to find your way if you need to move. Overnight lows of about 5°C at 900 m. A 3-season bag rated to about 4°C comfort, and a warm mat, should do. Allow more if you sleep cold.

Overnight rain11.8 mm Open ground · 600 m30 mph · gusts 51 mph Morning pack-upDampness possible Sleeping-bag warmthISO comfort rating about 4°C or lower

Moon overnight

Near-full moon

Illuminated disc: 99%
Moonrise: Outside this window
Moonset: Outside this window

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

Overnight window: 26 Oct, 17:00 GMT to 27 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.

Elevation reference (open ground)

300 m19 · very poor

Wind / gust: 25 mph / 43 mph
Typical / low: 10.5°C / 6.3°C · several hours
In cloud: 0% of modelled night
Condensation: High

600 m9 · very poor

Wind / gust: 30 mph / 51 mph
Typical / low: 10.5°C / 6.3°C · several hours
In cloud: 0% of modelled night
Condensation: High

900 m0 · very poor

Wind / gust: 37 mph / 60 mph
Typical / low: 8.9°C / 5.2°C · much of the night
In cloud: 60% of modelled night
Condensation: High

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

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

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

Daytime · exposed rockClimbing & scramblingBetaMixed conditions for exposed scrambling: gusts of 30–40 mph. Poor45 View detailsHide details

Generic exposed-rock guidance

Full climbing & scrambling outlook

Mixed conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 30–40 mph could throw you off balance on exposed moves and ridges. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.

Rock surfaceWet rock likelyPeak gust30-40 mphRain1.1 mm

Main factorsgusts of 30–40 mphwet rock likely

Representative rock around the summit and along available routes Sandstone with clay-rich rock Brownstones Formation

Origin: Sedimentary
Broad rock-response group: Sandstone or gritstone
Mapping: BGS Geology 50K · 1:50,000
Summit area: Sandstone or gritstone in 100% of 17 BGS samples within 350 m
Rock-response profile: High confidence

View the summit BGS record

Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.

Rock groups along the sampled routes

These are mapped rock groups, not separate weather forecasts or a ranking of route safety.

Pen Y Fan Horseshoe

sandstone or gritstone

Generic exposed scrambling terrain; BGS summit-area bedrock samples are 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 darkBetaMostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. View forecastClose forecast

After dark: aurora and stargazing

Night beginning 2026-10-26. All times are UK local time.

Aurora outlook

Nothing notable expected.

A broad activity outlook, not a forecast of a visible display. Cloud and activity can change before the night.

Stargazing

Poor sky conditions during the best available spell: 26 Oct, 19:00 GMT to 20:00 GMT.

Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars.

A bright moon is up all through the dark hours, washing out fainter stars and meteors.

Sky conditions through the night

Fully dark periods. Conditions can change between forecast hours.
Time	Viewing conditions
26 Oct, 18:50 GMT to 19:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 19:00 GMT to 20:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 20:00 GMT to 21:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 21:00 GMT to 22:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 22:00 GMT to 23:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Moonlight washes out the fainter stars. Limited model coverage.
26 Oct, 23:00 GMT to 27 Oct, 00:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars. Limited model coverage.
27 Oct, 00:00 GMT to 01:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars. Limited model coverage.
27 Oct, 01:00 GMT to 02:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars. Limited model coverage.
27 Oct, 02:00 GMT to 03:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars. Limited model coverage.
27 Oct, 03:00 GMT to 04:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars. Limited model coverage.
27 Oct, 04:00 GMT to 05:00 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars. Limited model coverage.
27 Oct, 05:00 GMT to 05:05 GMT	Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. Hazy, which dims the fainter stars. Moonlight washes out the fainter stars. Limited model coverage.

Moon, darkness and meteor showers

Near-full moon, about 99% illuminated.

Full darkness: 26 Oct, 18:50 GMT to 27 Oct, 05:05 GMT.

Moon times assume an open horizon. Hills can hide the Moon sooner. Moon-free does not mean cloud-free.

Southern Taurids are active on this night. Activity may be much lower away from the peak.

Orionids are active on this night. Activity may be much lower away from the peak.

Northern Taurids are active on this night. Activity may be much lower away from the peak.

Southern Taurids: peak around 10 October 2026.
Orionids: peak around 21 October 2026.
Northern Taurids: peak around 12 November 2026.
Leonids: peak around 18 November 2026.
Geminids: peak around 14 December 2026.
Ursids: peak around 22 December 2026.

Dates from the Royal Observatory Greenwich. Activity dates do not guarantee visible meteors. Look across a broad, dark sky, not only north.

Darkness of the surroundings

Estimated darkness rank 927 of 980 assessed peaks (1 is darkest), based on surrounding artificial light in 2021. This is not a measurement of tonight’s sky.

2021 artificial-light baseline, not measured sky brightness or a Bortle class. Changes to lighting, blue-rich LEDs, terrain screening, atmospheric scattering and cloud-reflected light are not resolved. Similar ranks are not meaningfully distinct. Darkness is not a recommendation to climb a summit at night.

VIIRS nighttime lights: Earth Observation Group, Payne Institute for Public Policy, Colorado School of Mines. Reprocessed by OpenGeoHub/OpenLandMap. Cropped and ranked by Mountain Weather.

Sky-weather grades exclude light pollution, terrain and thin haze. They are not mountain safety ratings. Check the mountain and camping forecast separately. Accessible lower viewpoints may be a better choice than summits.

Explore the dedicated aurora forecast, meteor shower forecast or dark-sky and astrophotography forecast.

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

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

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

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

This is about Pen y Fan on Monday 26 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.

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Pen y Fan weather forecast.

See the wind across Pen y Fan.

Choose your hill day.

The day on the hill

Wind

Cloud and visibility

Rain and ground

Warmth and kit

Daylight

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Pen Y Fan Horseshoe

After dark: aurora and stargazing

Aurora is unlikely on this night

Stargazing

Darkness of the surroundings

The day on the hill

Wind

Cloud and visibility

Rain and ground

Warmth and kit

Daylight

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Pen Y Fan Horseshoe

After dark: aurora and stargazing

Aurora is unlikely on this night

Stargazing

Darkness of the surroundings

The day on the hill

Things to watch

Wind

Cloud and visibility

Rain and ground

Warmth and kit

Daylight

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Pen Y Fan Horseshoe

After dark: aurora and stargazing

Aurora is unlikely on this night

Stargazing

Darkness of the surroundings

The day on the hill

Things to watch

Wind

Cloud and visibility

Rain and ground

Warmth and kit

Daylight

Forecast confidence

Full overnight outlook

Moon overnight

Elevation reference (open ground)

Full climbing & scrambling outlook

Rock groups along the sampled routes

Pen Y Fan Horseshoe

After dark: aurora and stargazing

Stargazing

Darkness of the surroundings

The day on the hill

Wind

Cloud and visibility

Rain and ground

Warmth and kit

Daylight

Forecast confidence

Full overnight outlook