The day on the hill
A poor day on the tops of Crib y Ddysgl, with drizzle for much of the day and cloud coming and going on the summit.
Wind
On the summit expect a south-easterly wind of 5–20 mph for most of the day, with gusts of 15–25 mph at the windiest. Lower down on the open hillside the wind will be light, under 10 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 in the late 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.
Rain and ground
Drizzle for much of the day. 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
Things could still change through the day, so keep an eye on the sky.
The Orionids are around their peak and clear, dark spells are forecast: worth a look after midnight. Displays vary, so no promises. Check the After dark forecast below for viewing times and limitations.
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.
Overnight · 17:00–08:00Wild campingBetaA reasonable night to camp, with a well-chosen pitch: about 3 mm of rain. 64Mixed · 600 m View detailsHide details
Full overnight outlook
A reasonable night to camp, with a well-chosen pitch. Light winds on open ground, gusting no more than about 25 mph. The wind swings from southerly to southeasterly overnight, so a pitch sheltered at dusk may not be by morning. Expect about 3 mm of rain, with rain while you pitch and still falling when you pack up. 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.
Moon overnight
Waxing gibbous moon
- Illuminated disc
- 72%
- Moonrise
- Outside this window
- Moonset
- 01:45 next morning BST
Extensive cloud may limit moonlight. 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)
- Wind / gust
- 9 mph / 17 mph
- Typical / low
- 8.2°C / 7.6°C · much of the night
- In cloud
- 0% of modelled night
- Condensation
- High
- Wind / gust
- 11 mph / 21 mph
- Typical / low
- 6.8°C / 6.4°C · much of the night
- In cloud
- 20% of modelled night
- Condensation
- High
- Wind / gust
- 13 mph / 24 mph
- Typical / low
- 5.0°C / 4.5°C · much of the night
- In cloud
- 20% 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. Poor1 View detailsHide details
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 basalt, a dark volcanic rock. It grips well when dry and can be very slippery when wet. It is often blocky and shattered, with loose rubble on ledges. On the usual routes up you may also cross volcanic tuff, which is rough and grippy when dry and usually still grips reasonably when wet. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Basalt is a dark volcanic rock. It grips well when dry and can be very slippery when wet. It is often blocky and shattered, with loose rubble on ledges. 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.
Snowdon Horseshoe
volcanic rock
Snowdon Llanberis
volcanic rock, slate or mudstone
Snowdon Miners Track
volcanic rock
Snowdon Pyg Track
volcanic rock
Snowdon Ranger Path
volcanic rock, sandstone or gritstone
Geological detail and BGS records
10 rock types appear in the mapped samples
Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.
Basalt is a dark volcanic rock. It grips well when dry and can be very slippery when wet. It is often blocky and shattered, with loose rubble on ledges.
BGS recordVolcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS recordRhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.
BGS recordVolcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS recordMudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS recordSandstone 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.
BGS recordSandstone 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.
BGS recordMudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS recordVolcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS recordVolcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS recordGeneric 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. View forecastClose forecast
After dark: aurora and stargazing
Night beginning 2026-10-20. All times are UK local time.
A noticeable aurora display is unlikely; any glow may be faint or camera-only
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
Good sky conditions during the best available spell: 21 Oct, 01:00 BST to 02:00 BST.
Some breaks in the cloud, so stars at times.
Moon-free dark sky: 21 Oct, 01:40 BST to 06:00 BST.
Sky conditions through the night
| Time | Viewing conditions |
|---|---|
| 20 Oct, 20:05 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 | Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars. |
| 20 Oct, 23:00 BST to 21 Oct, 00:00 BST | Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree. |
| 21 Oct, 00:00 BST to 01:00 BST | Mixed 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 | Good sky conditions Some breaks in the cloud, so stars at times. |
| 21 Oct, 02:00 BST to 03:00 BST | Mixed sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree. |
| 21 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. |
| 21 Oct, 04:00 BST to 05:00 BST | Poor sky conditions Mostly cloudy, so little chance of seeing the stars. |
| 21 Oct, 05:00 BST to 06:00 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, 01:40 BST.
Full darkness: 20 Oct, 20:05 BST to 21 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 814 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 Crib y Ddysgl 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.
About the research and your privacy · Already been out? Share that experience instead