Cloud-free timing: Cloudy early, clearing later.
A fine day on Clisham: summit wind broadly 5-15 mph, with gusts 10-20 mph during the afternoon (a moderate breeze). Little or no rain expected.
799 m summit in Lewis and Harris. Seven-day wind, cloud, rain and temperature forecast, updated 26 August 2026 at 15:32 UTC.
Clisham on Wednesday 26 August 2026: summit wind around 11 mph SE, gusting 15 mph; modelled cloud-free summit for 79% of daylight; feels like 7°C; 0.0 mm rain.
Conditions can change quickly with height. Use the day-by-day summit detail below, then check again close to departure.
Cloud-free timing: Cloudy early, clearing later.
A fine day on Clisham: summit wind broadly 5-15 mph, with gusts 10-20 mph during the afternoon (a moderate breeze). Little or no rain expected.
Cloud-free timing: Around 100% early, falling to around 80% later.
A fine day on Clisham: 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 3000-3300 m) - clear summits. Little or no rain expected.
A grey, cloudy day on Clisham: summit wind broadly 15-25 mph, with gusts 25-35 mph during the evening (strong winds). Cloud base around 100-400 m in the morning, lifting to 400-700 m around midday. Expect the top to stay in cloud for most or all of daylight, with no dependable break. Cloud is likely to hang lowest on northeastern slopes; the southwestern 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 19-28 mph, so treat the headline as mid-range.
A grey, cloudy day on Clisham: summit wind broadly 0-15 mph, with gusts 10-20 mph early in the morning (a moderate breeze). 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. Little or no rain expected.
Forecast confidence: Rain is possible, but forecast models differ by about 14 hours on when it arrives.
A grey, cloudy day on Clisham: summit wind broadly 5-15 mph, with gusts 10-20 mph during the afternoon (a moderate breeze). 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. 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.
from early morning into the evening. Leave exposed summits and ridges if thunder develops.
A grey, cloudy day on Clisham: summit wind broadly 0-20 mph, with gusts 15-25 mph early in the morning (a moderate breeze). A meaningful thunderstorm risk is indicated from early morning into the evening. Avoid committing to exposed ridges if storms begin to build. Cloud base mostly around 300–600 m through daylight. Expect the top to stay in cloud for most or all of daylight, with no dependable break. Some rain is likely, with around 2-5 mm indicated; timing and local totals remain uncertain.
Forecast confidence: Summit wind could be roughly 32-50 mph, which changes how difficult exposed walking may feel.
Burns and unbridged crossings may rise quickly. Assess them at the water and turn back if unsure.
A rough, clagged-in day on Clisham: summit wind broadly 25-45 mph, with gusts 55-65 mph early in the morning (storm-force winds). High spate risk based on forecast rainfall. Burns and unbridged crossings may become difficult or impassable. Most likely from around 00:00 until around 18:00. 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 500–800 m around midday and 700–1000 m by late afternoon. Expect the top to stay in cloud for most or all of daylight, with no dependable break. Cloud is likely to hang lowest on northern slopes; the southern 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. Cold on top: air temperature broadly 2 to 6°C, feeling around -2 to 2°C in the wind - wrap up. Confidence moderate (Summit wind could be roughly 32-50 mph, which changes how difficult exposed walking may feel) - the summit peak could reasonably be 32-50 mph, so treat the headline as mid-range.
Forecast run: 2026-08-26
Choose your dates to see whole-home stays ranked by driving time to useful route starts.
Accommodation links are affiliate links. Availability and prices may come from Snaptrip, Cottages.com or Stay22 partners for the dates you choose.
Mountain weather can differ sharply from conditions in the valley. Check official warnings, carry appropriate navigation and clothing, and be ready to change the plan. Read how Mountain Weather forecasts are produced and where their limits lie.