The day on the hill
A poor day on the tops of Tryfan, with strong, gusty winds and sleet or snow up high.
Things to watch
Burns could rise quickly from the morning into the afternoon. 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 45–55 mph at the windiest. Lower down on the open hillside it will be more like 10–20 mph. Gusts like that are strong enough to knock you off balance, so take care near edges and on narrow ridges.
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 mid-morning. Visibility could be very poor in the wetter spells. Mist or fog is possible in the valleys during the morning, clearing by about 9am.
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. It will feel colder later as the wind picks up. The freezing level falls through the day, to around 1100–1400 m by midday. 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. Things could still change through the day, so keep an eye on the sky.
Webcam view and cloud base
This image is unavailable. Please use the provider’s current webcam link below.
This image is unavailable. Please use the provider’s current webcam link below.
Earlier camera image, not current conditions. Camera feed timestamp: 20 October 2026, 18:45 BST. The image and cloud-base reading may not be from the same moment. Still images, not live video.
With thanks to University of London Graduate Mountaineering Club (ULGMC), Caseg Fraith Hut. Used with permission. Image analysis and overlays by Mountain Weather.
Earlier observation, not current conditions.
Earlier observations that day
- No cloud detected on the mapped slopes. The actual summit is not confirmed clear.
- No cloud detected on the mapped slopes. The actual summit is not confirmed clear.
- No cloud detected on the mapped slopes. The actual summit is not confirmed clear.
- No cloud detected on the mapped slopes. The actual summit is not confirmed clear.
- No cloud detected on the mapped slopes. The actual summit is not confirmed clear.
- No cloud detected on the mapped slopes. The actual summit is not confirmed clear.
- No cloud detected on the mapped slopes. The actual summit is not confirmed clear.
Camera-based estimates for the slopes in view, not the whole mountain. Heights are approximate and have not been independently checked. These observations do not replace the forecast.
Explore cloud-base observations, the camera view and daily downloads
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 above about 600 m (gusts of about 45 mph and about 5 mm of rain). Lower down, a poor night to camp on open ground. 19Poor · 600 m View detailsHide details
Full overnight outlook
Too windy for an exposed pitch above about 600 m. Lower down, a poor night to camp on open ground. Gusts reach about 45 mph around 900 m and nearer 35 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 about 5 mm of rain overnight and into the morning, so expect to pack a wet tent. 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. 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 / 33 mph
- Typical / low
- 5.3°C / 4.5°C · several hours
- In cloud
- 0% of modelled night
- Condensation
- Moderate
- Wind / gust
- 17 mph / 40 mph
- Typical / low
- 4.4°C / 3.7°C · much of the night
- In cloud
- 20% of modelled night
- Condensation
- Moderate
- Wind / gust
- 20 mph / 47 mph
- Typical / low
- 2.5°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 45–55 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 45–55 mph could throw you off balance on exposed moves and ridges. Cloud on the tops may make route-finding and retreat harder. The rock changes around the summit, with dolerite, volcanic tuff and mudstone or slate, so its grip and soundness vary as you go. Dolerite is a hard, dark, fine-grained rock. It grips well when dry and is fair when wet. It is usually solid, but it often breaks into blocky columns, so check blocks before you pull on them. Volcanic 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. 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.
The rock changes around the summit, with dolerite, volcanic tuff and mudstone or slate, so its grip and soundness vary as you go. The rock changes over short distances here, so check it directly before you commit to a move. Lichen, vegetation and seepage also 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.
Glyderau Ogwen
slate or mudstone, volcanic rock, sandstone or gritstone
Geological detail and BGS records
11 rock types appear in the mapped samples
No single rock family dominates the summit-area samples, so the forecast uses cautious mixed-rock guidance. The summit pin is shown separately and may not represent nearby crags. Route samples add context where available.
Dolerite is a hard, dark, fine-grained rock. It grips well when dry and is fair when wet. It is usually solid, but it often breaks into blocky columns, so check blocks before you pull on them.
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 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 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 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 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 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 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 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 3.7 (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
Poor sky conditions during the best available spell: 21 Oct, 22:00 BST to 23:00 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
| Time | Viewing conditions |
|---|---|
| 21 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. |
| 21 Oct, 21:00 BST to 22:00 BST | Poor sky conditions Some forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree. |
| 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 forecasts show clear spells, others keep it cloudy; check again nearer the time. Forecast models disagree. |
| 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. |
| 22 Oct, 03:00 BST to 04:00 BST | Poor sky conditions Mostly cloudy, so little chance of seeing the stars. Rain at times. |
| 22 Oct, 04:00 BST to 05:00 BST | Poor sky conditions Mostly cloudy, so little chance of seeing the stars. |
| 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 837 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.
Terrain at this viewpoint
Approximate terrain horizon at Tryfan. Trees, buildings and nearby obstacles are not included.
Approximate bare-earth horizon, not surveyed sightlines. Narrow ridges may fall between samples. Trees, buildings and very close obstacles are not resolved. Valid only at the named summit coordinate, not on its slopes or at a lower campsite.
Mapzen Terrain Tiles. Europe terrain produced using Copernicus data and information funded by the European Union, EU-DEM layers. UK terrain: Environment Agency copyright and/or database right 2015. Global terrain: USGS and NOAA.
Contains Welsh Government public sector information licensed under the Open Government Licence v3.0.
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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