Y Garn weather forecast.

Cloud-free timing: Cloudy early, clearing later.

A mixed day on Y Garn: summit wind broadly 20-35 mph, with gusts 40-50 mph during the morning (gale-force winds). Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops. Cloud base around 500–800 m in the morning, lifting to 1200–1500 m around midday and 3000–3300 m by late afternoon. Summit cloud should lift later, bringing a better chance of clear views. Little or no rain expected.

Forecast confidence: Thunderstorm timing is inherently uncertain and may shift by several hours.

Cloud-free timing: Cloudy early, clearing later.

A mixed day on Y Garn: summit wind broadly 5-25 mph, with gusts 20-30 mph early in the morning (fresh and blowy). Thunderstorms are a significant hazard from around midday into the evening. Exposed summits and ridges are a poor choice while storms are nearby. Cloud base around 500-800 m in the morning, lifting to 1400-1700 m around midday. Summit cloud should lift later, bringing a better chance of clear views. Some rain is likely, with up to around 2 mm indicated; timing and local totals remain uncertain.

Forecast confidence: Thunderstorm timing is inherently uncertain and may shift by several hours.

Cloud-free timing: Around 0% early, improving to around 20% later.

A rough, clagged-in day on Y Garn: summit wind broadly 15-30 mph, with gusts 30-40 mph early in the morning (strong winds). Thunderstorms are a significant hazard from the morning into the evening. Exposed summits and ridges are a poor choice while storms are nearby. Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops. Cloud base mostly around 400–700 m through daylight. Expect clag for much of the day, though a brief clearance is possible during the evening. Cloud is likely to hang lowest on southeastern slopes; the northwestern side should see somewhat higher bases and better breaks. A persistently wet day is possible, with around 10-20 mm indicated; local totals could vary considerably. Confidence moderate (forecast models agree on the walking impact of the wind) - the summit peak could reasonably be 22-29 mph, so treat the headline as mid-range.

Forecast confidence: Thunderstorm timing is inherently uncertain and may shift by several hours.

A rough, clagged-in day on Y Garn: summit wind broadly 15-25 mph, with gusts 25-35 mph during the afternoon (strong winds). A meaningful thunderstorm risk is indicated from the morning into the afternoon. Avoid committing to exposed ridges if storms begin to build. The ground is likely to be wet after recent rain. There could be a spate risk based on forecast rainfall. Burns and unbridged crossings may rise quickly. Most likely from around 02:00 until around 20:00. Cloud base mostly around 400–700 m through daylight. Expect the top to stay in cloud for most or all of daylight, with no dependable break. Cloud is likely to hang lowest on western slopes; the eastern side should see somewhat higher bases and better breaks. A persistently wet day is possible, with around 10-20 mm indicated; local totals could vary considerably. Confidence moderate (forecast models agree on the walking impact of the wind) - the summit peak could reasonably be 19-25 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.

Forecast confidence: Thunderstorm timing is inherently uncertain and may shift by several hours.

A rough, clagged-in day on Y Garn: summit wind broadly 10-30 mph, with gusts 25-35 mph early in the morning (strong winds). A meaningful thunderstorm risk is indicated from the morning into the evening. Avoid committing to exposed ridges if storms begin to build. The ground is likely to be wet after recent rain. There could be a spate risk based on forecast rainfall. Burns and unbridged crossings may rise quickly. Most likely from around 08:00 until around 02:00 the following day. Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops. Cloud base mostly around 400–700 m through daylight. Expect the top to stay in cloud for most or all of daylight, with no dependable break. Cloud is likely to hang lowest on southwestern slopes; the northeastern side should see somewhat higher bases and better breaks. A persistently wet day is possible, with around 5-10 mm indicated; local totals could vary considerably. Confidence moderate (forecast models agree on the walking impact of the wind) - the summit peak could reasonably be 17-30 mph, so treat the headline as mid-range.

Forecast confidence: Thunderstorm timing is inherently uncertain and may shift by several hours.

Cloud-free timing: Around 0% early, improving to around 40% later.

A rough, clagged-in day on Y Garn: summit wind broadly 15-35 mph, with gusts 35-45 mph during the evening (strong winds). Thunderstorms are a significant hazard from early morning into the evening. Exposed summits and ridges are a poor choice while storms are nearby. The ground is likely to be wet after recent rain. There could be a spate risk based on forecast rainfall. Burns and unbridged crossings may rise quickly. Most likely from around 11:00 until around 23:00. Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops. Cloud base mostly around 400–700 m through daylight. The top is likely to drift in and out of cloud, with the best chance of a view during the afternoon. Cloud is likely to hang lowest on southwestern slopes; the northeastern side should see somewhat higher bases and better breaks. A persistently wet day is possible, with around 5-10 mm indicated; local totals could vary considerably. Confidence moderate (Summit wind could be roughly 22-35 mph, which changes how difficult exposed walking may feel) - the summit peak could reasonably be 22-35 mph, so treat the headline as mid-range.

Forecast confidence: A low thunderstorm risk remains difficult to time precisely.

Cloud-free timing: Around 0% early, improving to around 100% later.

A mixed day on Y Garn: summit wind broadly 20-35 mph, with gusts 40-50 mph during the afternoon (gale-force winds). Thunderstorms are possible from the morning into the afternoon. Keep an escape route from exposed ridges and descend if thunder develops. The ground is likely to be wet after recent rain. There could be a spate risk based on forecast rainfall. Burns and unbridged crossings may rise quickly. Most likely from around 02:00 until around 23:00. Much calmer lower down - generally 10-20 mph in the valley, rising towards the tops. Cloud base around 400–700 m in the morning, lifting to 500–800 m around midday and 1000–1300 m by late afternoon. 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 is likely to hang lowest on western slopes; the eastern side should see somewhat higher bases and better breaks. Some rain is likely, with around 5-10 mm indicated; timing and local totals remain uncertain. Confidence moderate (Summit wind could be roughly 25-40 mph, which changes how difficult exposed walking may feel) - the summit peak could reasonably be 25-40 mph, so treat the headline as mid-range.