Moel Siabod weather forecast.

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

Cloud-free timing: Around 33% early, falling to around 0% later.

A rough, clagged-in day on Moel Siabod: summit wind broadly 15-40 mph, with gusts 40-50 mph around midday (gale-force winds). Thunderstorms are a significant hazard from late afternoon into the evening. Exposed summits and ridges are a poor choice while storms are nearby. High spate risk based on forecast rainfall. Burns and unbridged crossings may become difficult or impassable. Most likely from around 08:00 until around 01:00 the following day. Much calmer lower down - generally 5-15 mph in the valley, rising towards the tops. A cloud layer may sit from about 400-700 m up to 700-1000 m. You may climb through it on the mid slopes, with a chance the summit stands clear above; this is not guaranteed. 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.

A grey, cloudy day on Moel Siabod: 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 afternoon. Exposed summits and ridges are a poor choice while storms are nearby. The ground is likely to be wet after recent rain. 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 western slopes; the eastern side should see somewhat higher bases and better breaks. Some rain is likely, with around 2-5 mm indicated; timing and local totals remain uncertain. Confidence moderate (Summit wind could be roughly 18-31 mph, which changes how difficult exposed walking may feel) - the summit peak could reasonably be 18-31 mph, so treat the headline as mid-range.

Forecast confidence: Summit wind could be roughly 19-37 mph, which changes how difficult exposed walking may feel.

A grey, cloudy day on Moel Siabod: summit wind broadly 15-30 mph, with gusts 30-40 mph during the evening (strong winds). The ground is likely to be wet after recent rain. 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. Some rain is likely, with around 2-5 mm indicated; timing and local totals remain uncertain. Confidence moderate (Summit wind could be roughly 19-37 mph, which changes how difficult exposed walking may feel) - the summit peak could reasonably be 19-37 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 rough, clagged-in day on Moel Siabod: summit wind broadly 25-45 mph, with gusts 50-60 mph during the evening (gale-force winds). Thunderstorms are a significant hazard from the 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 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. Some rain is likely, with around 5-10 mm indicated; timing and local totals remain uncertain. Confidence moderate (Summit wind could be roughly 22-44 mph, which changes how difficult exposed walking may feel) - the summit peak could reasonably be 22-44 mph, so treat the headline as mid-range.

Forecast confidence: Summit wind could be roughly 37-56 mph, which changes how difficult exposed walking may feel.

Cloud-free timing: Cloudy early, clearing later.

A wild day on Moel Siabod: summit wind broadly 35-50 mph, with gusts 55-65 mph during the afternoon (storm-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. Cloud base around 400–700 m in the morning, lifting to 900–1200 m around midday and 1700–2000 m by late afternoon. Summit cloud should lift later, bringing a better chance of clear views. 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 2-5 mm indicated; timing and local totals remain uncertain. Cold on top: air temperature broadly 4 to 8°C, feeling around -2 to 2°C in the wind - wrap up. Low confidence (Summit wind could be roughly 37-56 mph, which changes how difficult exposed walking may feel) - the summit peak could be anywhere from 37 to 56 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 confidence: Rain is possible, but forecast models differ by about 14 hours on when it arrives.

Cloud-free timing: Cloudy early, clearing later.

A mixed day on Moel Siabod: summit wind broadly 20-30 mph, with gusts 35-45 mph around midday (strong winds). Much calmer lower down - generally 10-20 mph in the valley, rising towards the tops. Any cloud sits well above the tops (base 900-1800 m) - clear summits. 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 up to around 2 mm indicated; timing and local totals remain uncertain. Cold on top: air temperature broadly 6 to 10°C, feeling around 0 to 4°C in the wind - wrap up. Confidence moderate (forecast models agree on the walking impact of the wind) - the summit peak could reasonably be 22-31 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.