Garreg Lwyd weather forecast.

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

Cloud-free timing: Cloudier around midday at about 25%; around 100% early and 100% later.

A mixed day on Garreg Lwyd: summit wind broadly 10-30 mph, with gusts 30-40 mph early in the morning (strong winds). Thunderstorms are forecast from early morning into the evening. Avoid exposed summits and ridges during the risk period. Much calmer lower down - generally 0-10 mph in the valley, rising towards the tops. Cloud base around 900–1200 m in the morning, then around 400–700 m around midday and 900–1200 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. Some rain is likely, with around 2-5 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 60% later.

A wild day on Garreg Lwyd: summit wind broadly 10-20 mph, with gusts 20-30 mph early in the morning (fresh and blowy). 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. High spate risk based on forecast rainfall. Burns and unbridged crossings may become difficult or impassable. Most likely from around 02:00 until around 04:00 the following day. Cloud base around 400–700 m in the morning, then around 900–1200 m around midday and 600–900 m by late afternoon. The top is likely to drift in and out of cloud, with the best chance of a view from midday into 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 10-20 mm indicated; local totals could vary considerably.

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 grey, cloudy day on Garreg Lwyd: summit wind broadly 15-30 mph, with gusts 35-45 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. 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. Some rain is likely, with around 5-10 mm indicated; timing and local totals remain uncertain. Confidence moderate (Summit wind could be roughly 16-37 mph, which changes how difficult exposed walking may feel) - the summit peak could reasonably be 16-37 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 mixed day on Garreg Lwyd: summit wind broadly 15-30 mph, with gusts 30-40 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 00:00 until around 03:00 the following day. Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops. Cloud base around 400–700 m in the morning, then around 900–1200 m around midday and 400–700 m by late afternoon. The top is likely to drift in and out of cloud, with the best chance of a view from midday into the afternoon. Cloud is likely to hang lowest on southwestern slopes; the northeastern 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 (forecast models agree on the walking impact of the wind) - the summit peak could reasonably be 21-29 mph, so treat the headline as mid-range.

Forecast confidence: Forecast models disagree materially on rainfall amounts.

Cloud-free timing: Cloudy early, clearing later.

A wild day on Garreg Lwyd: summit wind broadly 25-40 mph, with gusts 40-50 mph around midday (gale-force winds). The ground is likely to be wet after recent rain. Much calmer lower down - generally 15-25 mph in the valley, rising towards the tops. Any cloud sits well above the tops (base 700-1200 m) - clear summits. Cloud is likely to hang lowest on western slopes; the eastern side should see somewhat higher bases and better breaks. Little or no rain expected. Confidence moderate (forecast models agree on the walking impact of the wind) - the summit peak could reasonably be 28-39 mph, so treat the headline as mid-range.

Forecast confidence: Rain is possible, but forecast models differ by about 12 hours on when it arrives.

Cloud-free timing: Cloudy early, clearing later.

A mixed day on Garreg Lwyd: summit wind broadly 10-30 mph, with gusts 30-40 mph early in the morning (strong winds). Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops. Some rain is likely, with around 2-5 mm indicated; timing and local totals remain uncertain. Bright spells with UV up to 5 - sunscreen on exposed skin. Confidence moderate (forecast models agree on the walking impact of the wind) - the summit peak could reasonably be 19-27 mph, so treat the headline as mid-range.