Craig Cwm Silyn weather forecast.

734 m summit forecast for wind, cloud, rain and temperature. Updated from the Thursday 6 August 2026 model run.

Seven-day Craig Cwm Silyn forecast.

Conditions can change quickly with height. Use the day-by-day summit detail below, then check again close to departure.

High confidence
Wind29 mph W Gusts41 mph Feels3°C Rain0.2 mm Cloud-free summit38% Cloud base637 m Freezing level2,100 m Daylight05:41–21:02 · 15.3 h

A grey, cloudy day on Craig Cwm Silyn: summit wind broadly 15-35 mph, with gusts 35-45 mph early in the morning (gale-force winds). Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops. Cloud base 600-1100 m - the top is likely to drift in and out of cloud, with the best chance of a view from late afternoon into the evening. Cloud will be lowest on the W slopes, down to about 500-800 m; the E side should be clearer, lifting to around 700-1000 m. Little or no rain expected.

High confidence
Wind15 mph SW Gusts20 mph Feels8°C Rain0.0 mm Cloud-free summit81% Cloud base1,072 m Freezing level2,990 m Daylight05:43–21:00 · 15.3 h

A fine day on Craig Cwm Silyn: summit wind broadly 5-20 mph, with gusts 15-25 mph around midday (fresh and blowy). Little or no rain expected.

Medium confidence
Wind20 mph SW Gusts28 mph Feels7°C Rain0.3 mm Cloud-free summit88% Cloud base1,051 m Freezing level3,330 m Daylight05:45–20:58 · 15.2 h

A fine day on Craig Cwm Silyn: summit wind broadly 10-25 mph, with gusts 25-35 mph during the evening (fresh and blowy). Any cloud sits well above the tops (base 700-1300 m) - clear summits. Little or no rain expected. Bright spells with UV up to 6 - sunscreen on exposed skin. Confidence moderate (ensemble members show a moderate spread) - the summit peak could reasonably be 16-24 mph, so treat the headline as mid-range. Cloud base is the least certain part of this - the models are only moderately agreed, so it could sit a couple of hundred metres either way.

Low confidence
Wind19 mph W Gusts23 mph Feels12°C Rain0.0 mm Cloud-free summit94% Cloud base3,083 m Freezing level2,800 m Daylight05:46–20:56 · 15.2 h

A fine day on Craig Cwm Silyn: summit wind broadly 5-25 mph, with gusts 20-30 mph early in the morning (fresh and blowy). Much calmer lower down - generally 0-10 mph in the valley, rising towards the tops. Any cloud sits well above the tops (base 1100-3100 m) - clear summits. Little or no rain expected. Bright spells with UV up to 6 - sunscreen on exposed skin. Low confidence (ensemble members are widely spread) - the summit peak could be anywhere from 10 to 26 mph; check again nearer the time. Treat the cloud base with caution - the models disagree on humidity, so it could be well above or below the figure given.

Low confidence
Wind9 mph N Gusts12 mph Feels11°C Rain0.0 mm Cloud-free summit81% Cloud base872 m Freezing level2,600 m Daylight05:48–20:54 · 15.1 h

A fine day on Craig Cwm Silyn: summit wind broadly 5-15 mph, with gusts 5-15 mph early in the morning (a moderate breeze). Little or no rain expected. Bright spells with UV up to 6 - sunscreen on exposed skin. Low confidence (ensemble members are widely spread) - the summit peak could be anywhere from 5 to 13 mph; check again nearer the time. Cloud base is the least certain part of this - the models are only moderately agreed, so it could sit a couple of hundred metres either way.

Low confidence
Wind22 mph S Gusts31 mph Feels15°C Rain0.6 mm Cloud-free summit81% Cloud base1,084 m Freezing level3,100 m Daylight05:50–20:52 · 15.1 h

A mixed day on Craig Cwm Silyn: summit wind broadly 10-25 mph, with gusts 25-35 mph early in the morning (strong winds). Much calmer lower down - generally 0-10 mph in the valley, rising towards the tops. Little or no rain expected. Bright spells with UV up to 6 - sunscreen on exposed skin. Low confidence (ensemble members are widely spread) - the summit peak could be anywhere from 10 to 33 mph; check again nearer the time. Cloud base is the least certain part of this - the models are only moderately agreed, so it could sit a couple of hundred metres either way.

Low confidence
Wind29 mph S Gusts40 mph Feels17°C Rain0.0 mm Cloud-free summit75% Cloud base709 m Freezing level3,250 m Daylight05:51–20:50 · 15.0 h

A mixed day on Craig Cwm Silyn: summit wind broadly 20-35 mph, with gusts 35-45 mph early in the morning (strong winds). Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops. Cloud base 500-1000 m - the top is likely to drift in and out of cloud, with the best chance of a view from early morning into the afternoon. Little or no rain expected. Low confidence (ensemble members are widely spread) - the summit peak could be anywhere from 20 to 43 mph; check again nearer the time. Cloud base is the least certain part of this - the models are only moderately agreed, so it could sit a couple of hundred metres either way.

Forecast run: 2026-08-06

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