The day on the hill
On Waun Fach: summit wind broadly 10-25 mph, with gusts 20-30 mph at times (a moderate breeze).
Cloud & views
Cloud base around 600–900 m in the morning, lifting to 1000–1300 m around midday and 1600–1900 m by late afternoon. Summit cloud is extensive early, becoming less frequent later.
Cloud-height uncertainty could put the summit in or out of cloud. Clear spells may be difficult to time.
Cloud may hang lower on northwestern slopes and lift somewhat on the southeastern side, but local terrain can differ. Sunny spells are possible away from summit cloud, but may not reach the top while it is in cloud.
Drizzle is forecast at times. The forecast total is up to around 2 mm, but local amounts will vary.
Forecast confidence
Cloud height remains uncertain, especially where it is close to summit level. Cloud-height uncertainty could put the summit in or out of cloud, even where forecasts agree on the wider cloud cover.
Cloud-free timing: Around 25% early, improving to around 95% later.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 6.1 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.
- Early
- 0 h
- Midday
- 3.1 h
- Later
- 2 h
Overnight forecast: 17:00–08:00 (UK local time), in Wild camping below.
Overnight · 17:00–08:00Wild campingBetaA broadly very good night on a well-chosen pitch. 93/100Excellent · 600 m View detailsHide details
Full overnight outlook
Open-hillside camping looks very good overall around 600 m (93/100). It may be breezy on open ground, with gusts near 25 mph. Little overnight rain is forecast.
Moon overnight
Waxing gibbous moon
- Illuminated disc
- 92%
- Moonrise
- 18:04 BST
- Moonset
- 04:07 next morning BST
Clear spells may allow a view of the Moon. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 23 Sep, 17:00 BST to 24 Sep, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
- Wind / gust
- 11 mph / 20 mph
- Typical / low
- 9.0°C / 8.5°C · much of the night
- In cloud
- 0% of modelled night
- Condensation
- Low
- Wind / gust
- 13 mph / 24 mph
- Typical / low
- 9.0°C / 8.5°C · much of the night
- In cloud
- 0% of modelled night
- Condensation
- Low
Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 6°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.
Open-hillside reference. A sheltered pitch may be calmer; cols and ridges may be much windier. Tent design and the exact pitch still matter. Read about sleeping-bag comfort ratings, pitching in strong winds or using the wild-camping forecast.
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Daytime · exposed rockClimbing & scramblingBetaWet rock is likely. Poor33/100 View detailsHide details
Full climbing & scrambling outlook
Conditions for exposed scrambling look poor (33/100). Rain during the climbing period 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. Representative samples along available mapped routes also include Interbedded argillaceous rocks and [subequal/subordinate] sandstone, so rock character and wet-weather behaviour may change across the mountain.
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.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Waun Fach Black Mountains
sandstone or gritstone
Geological detail and BGS records
3 rock types appear across the available route samples
The summit type remains the forecast's cautious rock-response reference. Other mapped types show where conditions may behave differently elsewhere on the mountain.
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.
BGS recordUsually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully.
BGS recordUsually rough and grippy when dry. Damp sandstone and gritstone can feel greasy, and saturated sandstone may be weakened, so let the rock dry fully.
BGS recordGeneric 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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Overnight · Aurora, stars & meteorsAfter darkBetaClearer spells are possible, but other forecasts keep much of the sky obscured by cloud. View forecastClose forecast
After dark: aurora and stargazing
Night beginning 2026-09-23. All times are UK local time.
Only a small chance of aurora on this night
Forecast activity gives only a small prospect here, most likely a faint glow picked up by a camera. Forecast activity peaks near Kp 5.3 on the 0 to 9 scale.
Activity can change at short notice. Check again on the night.
Stargazing
Mixed sky conditions during the best available spell: 24 Sep, 03:00 BST to 04:00 BST.
Clearer spells are possible, but other forecasts keep much of the sky obscured by cloud.
Moon-free dark sky: 24 Sep, 04:00 BST to 05:05 BST.
Sky conditions through the night
| Time | Viewing conditions |
|---|---|
| 23 Sep, 21:05 BST to 22:00 BST | Mixed sky conditions Clearer spells are possible, but other forecasts keep much of the sky obscured by cloud. Forecast models disagree. |
| 23 Sep, 22:00 BST to 23:00 BST | Poor sky conditions Clearer spells are possible, but other forecasts keep much of the sky obscured by cloud. Forecast models disagree. |
| 23 Sep, 23:00 BST to 24 Sep, 00:00 BST | Mixed sky conditions Clearer spells are possible, but other forecasts keep much of the sky obscured by cloud. Forecast models disagree. |
| 24 Sep, 00:00 BST to 01:00 BST | Poor sky conditions Clearer spells are possible, but other forecasts keep much of the sky obscured by cloud. Forecast models disagree. |
| 24 Sep, 01:00 BST to 02:00 BST | Poor sky conditions Clearer spells are possible, but other forecasts keep much of the sky obscured by cloud. Forecast models disagree. |
| 24 Sep, 02:00 BST to 03:00 BST | Poor sky conditions Cloud is likely to obscure much of the sky. Moonlight washes out fainter stars. |
| 24 Sep, 03:00 BST to 04:00 BST | Mixed sky conditions Clearer spells are possible, but other forecasts keep much of the sky obscured by cloud. Forecast models disagree. |
| 24 Sep, 04:00 BST to 05:00 BST | Mixed sky conditions Cloud is likely to obscure much of the sky. |
| 24 Sep, 05:00 BST to 05:05 BST | Mixed sky conditions Clearer spells are possible, but other forecasts keep much of the sky obscured by cloud. Forecast models disagree. |
Moon, darkness and meteor showers
Gibbous moon, about 92% illuminated.
Moonrise around 23 Sep, 18:05 BST.
Moonset around 24 Sep, 04:00 BST.
Full darkness: 23 Sep, 21:05 BST to 24 Sep, 05:05 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.
- Draconids: peak around 9 October 2026.
- 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 878 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.
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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