Forecast confidence: Forecast models disagree materially on rainfall amounts.
Burns and unbridged crossings may rise quickly. Assess them at the water and turn back if unsure.
Cloud-free timing: Around 25% early, improving to around 55% later.
A mixed day on Pen y Fan: summit wind broadly 20-30 mph, with gusts 35-45 mph during the morning (strong winds). There could be a spate risk based on forecast rainfall. Burns and unbridged crossings may rise quickly. Most likely from around 01:00 until around 13:00. Cloud base around 800–1100 m in the morning, lifting to 1000–1300 m around midday and 1400–1700 m by late afternoon. Summit cloud should lift later, bringing a better chance of clear views. Cloud height is close to summit level at times, so small local changes could put the top in or out of cloud. Cloud is likely to hang lowest on western slopes; the eastern side should see somewhat higher bases and better breaks. Sunshine is likely to be limited to about 1 hour through breaks in the cloud. Some rain is likely, with up to around 2 mm indicated; timing and local totals remain uncertain. Cloud base is the least certain part of this - it could sit a couple of hundred metres either way, especially where it is close to summit level.
Sunshine and sky
Limited sunny breaks. Any sunshine is likely to come through limited breaks.
These are direct modelled sunshine hours during daylight, not the probability of sunshine. Cloud cover and summit cloud are assessed separately in the forecast above. Local hill cloud can still make an individual summit brighter or duller than the surrounding model grid.
Overnight · 6 p.m.–9 a.m.Wild campingBetaGusts near 40 mph make meaningful shelter important. 81/100Good · 600 m View detailsHide details
Full overnight outlook
Open-hillside camping looks promising overall around 600 m (81/100). A lower pitch near 300 m looks more comfortable; conditions are less suitable by 900 m. Open-ground gusts may reach about 40 mph; seek meaningful shelter. Peak gusts increase from about 30 mph at 300 m to 40 mph at 900 m. Little overnight rain is expected. From around 900 m upward, pitches may spend part of the night in cloud, with high condensation risk, persistent damp and poor visibility; ventilation will matter. The coldest temperature falls from about 9°C at 300 m to 7.1°C at 900 m.
Elevation reference (open ground)
- Wind / gust
- 16 / 29 mph
- Typical / low
- 9.9° / 9.0°C · several hours
- In cloud
- Unlikely
- Condensation
- Moderate
- Wind / gust
- 20 / 35 mph
- Typical / low
- 9.9° / 9.0°C · several hours
- In cloud
- Unlikely
- Condensation
- Moderate
- Wind / gust
- 23 / 41 mph
- Typical / low
- 7.9° / 7.1°C · much of the night
- In cloud
- 56% of night
- Condensation
- High
Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 6°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.
Open-hillside reference. A sheltered pitch may be calmer; cols and ridges may be much windier. Tent design and the exact pitch still matter. Read about sleeping-bag comfort ratings, pitching in strong winds or using the wild-camping forecast.
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Daytime · exposed rockClimbing & scramblingBetaGusts near 40 mph increase the seriousness of exposed ground. 0/100Poor · Very poor View detailsHide details
Full climbing & scrambling outlook
Conditions for exposed scrambling look very poor (0/100). Rain during the useful part of the day is likely to leave rock wet and more slippery. The mapped summit rock is Interbedded sandstone and [subequal/subordinate] argillaceous rocks (Brownstones Formation). Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Gusts may reach about 40 mph; crosswinds can make exposed ridges substantially more serious.
Usually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully. Summit-point mapping plus representative BGS bedrock samples along available GPX routes. These are not continuous geological surveys; contacts, superficial deposits and the exposed rock on individual holds may differ.
Generic exposed scrambling terrain; mapped summit-point bedrock is included where available, but route grade, exact rock, polish, drainage and escape options remain unresolved. Contains British Geological Survey materials © UKRI 2026. How to use the climbing and scrambling forecast.
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Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit
For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.
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