The day on the hill
A wild day on the tops of Crib Goch, with very strong, gusty 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 from the morning 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 5–40 mph for most of the day, with gusts of 50–60 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 could be very poor in the wetter spells.
Rain and ground
Sleet is possible on the tops, and it could turn to snow if it is a little colder. Heavy rain at first, clearing by mid-afternoon. Expect 10–20 mm in total, measured as melted water, so any snow would lie deeper. Totals are uncertain and could be higher.
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 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 6:10pm, 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.
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 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 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
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. Dry to pitch, then some light rain overnight, easing by morning, though the tent may still be wet. 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. A cold night, down to about 2°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.
Moon overnight
Waxing gibbous moon
- Illuminated disc
- 80%
- Moonrise
- Outside this window
- Moonset
- 03:03 next morning BST
Extensive cloud may limit moonlight. 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)
- Wind / gust
- 14 mph / 31 mph
- Typical / low
- 5.5°C / 4.6°C · a brief spell
- In cloud
- 0% of modelled night
- Condensation
- Moderate
- Wind / gust
- 17 mph / 38 mph
- Typical / low
- 4.8°C / 3.8°C · much of the night
- In cloud
- 27% of modelled night
- Condensation
- Moderate
- Wind / gust
- 20 mph / 44 mph
- Typical / low
- 2.6°C / 1.8°C · much of the night
- In cloud
- 27% of modelled night
- Condensation
- Moderate
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.
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Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 50–60 mph. Poor0 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. Gusts of 50–60 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 rhyolite, 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. 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 basalt, which grips well when dry and can be very 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.
Rhyolite 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. 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 Miners Track
volcanic rock
Snowdon Pyg Track
volcanic rock
Geological detail and BGS records
4 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.
Rhyolite 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 recordBasalt 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 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.
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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 2026-10-21. 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 3.7 (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: 21 Oct, 22:00 BST to 23:00 BST.
Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars.
Moon-free dark sky: 22 Oct, 03:00 BST to 06:00 BST.
Sky conditions through the night
| Time | Viewing conditions |
|---|---|
| 21 Oct, 20:05 BST to 21:00 BST | Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree. |
| 21 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. |
| 21 Oct, 22:00 BST to 23:00 BST | Mixed sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars. |
| 21 Oct, 23:00 BST to 22 Oct, 00:00 BST | Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Moonlight washes out the fainter stars. |
| 22 Oct, 00:00 BST to 01:00 BST | Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. 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. Rain at times. 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. Rain at times. Hazy, which dims the fainter stars. |
| 22 Oct, 03:00 BST to 04:00 BST | Poor sky conditions Mostly cloudy, so little chance of seeing the stars. |
| 22 Oct, 04:00 BST to 05:00 BST | Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. |
| 22 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 80% illuminated.
Moonset around 22 Oct, 03:00 BST.
Full darkness: 21 Oct, 20:05 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 807 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.
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