Allt-Fawr weather forecast.

698 m summit in Eryri (Snowdonia). Seven-day wind, cloud, rain and temperature forecast, updated 27 August 2026 at 04:40 UTC.

At a glance

Today on Allt-Fawr.

Allt-Fawr on Thursday 27 August 2026: summit wind around 29 mph E, gusting 40 mph; modelled cloud-free summit for 14% of daylight; feels like 13°C; 17.3 mm rain.

Medium confidenceHow the forecast works

Seven-day Allt-Fawr forecast.

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

Medium confidence
Wind29 mph E Gusts40 mph Feels13°C Rain17.3 mm Cloud-free summit14% Cloud base511 m Freezing level2,980 m Daylight06:16–20:17 · 14.0 h

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

Thunder risk: high

from late afternoon into the evening. Leave exposed summits and ridges if thunder develops.

High spate risk

Burns and unbridged crossings may rise quickly. Assess them at the water and turn back if unsure.

Cloud-free timing: Around 67% early, falling to around 0% later.

A rough, clagged-in day on Allt-Fawr: summit wind broadly 15-35 mph, with gusts 35-45 mph during the morning (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. Cloud base around 700–1000 m in the morning, lowering to 500–800 m around midday and 400–700 m by late afternoon. Expect clag for much of the day, though a brief clearance is possible during the morning. A persistently wet day is possible, with around 10-20 mm indicated; local totals could vary considerably.

Medium confidence
Wind23 mph W Gusts32 mph Feels11°C Rain3.4 mm Cloud-free summit7% Cloud base456 m Freezing level2,810 m Daylight06:18–20:14 · 13.9 h

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

Thunder risk: high

from early morning into the afternoon. Leave exposed summits and ridges if thunder develops.

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

A grey, cloudy day on Allt-Fawr: summit wind broadly 10-30 mph, with gusts 25-35 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 clag for much of the day, though a brief clearance is possible during 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 2-5 mm indicated; timing and local totals remain uncertain. Confidence moderate (Summit wind could be roughly 15-26 mph, which changes how difficult exposed walking may feel) - the summit peak could reasonably be 15-26 mph, so treat the headline as mid-range.

Medium confidence
Wind24 mph SW Gusts34 mph Feels8°C Rain4.3 mm Cloud-free summit0% Cloud base467 m Freezing level2,938 m Daylight06:20–20:12 · 13.9 h

Forecast confidence: Summit wind could be roughly 18-36 mph, which changes how difficult exposed walking may feel.

A grey, cloudy day on Allt-Fawr: 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 18-36 mph, which changes how difficult exposed walking may feel) - the summit peak could reasonably be 18-36 mph, so treat the headline as mid-range.

Medium confidence
Wind32 mph SW Gusts45 mph Feels9°C Rain6.2 mm Cloud-free summit36% Cloud base662 m Freezing level2,719 m Daylight06:21–20:10 · 13.8 h

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

Thunder risk: high

from the morning into the evening. Leave exposed summits and ridges if thunder develops.

Spate watch

Burns and unbridged crossings may rise quickly. Assess them at the water and turn back if unsure.

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

A rough, clagged-in day on Allt-Fawr: summit wind broadly 20-35 mph, with gusts 40-50 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 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.

Medium confidence
Wind40 mph W Gusts56 mph Feels2°C Rain2.4 mm Cloud-free summit64% Cloud base938 m Freezing level1,930 m Daylight06:23–20:08 · 13.8 h

Forecast confidence: Forecast models disagree on whether meaningful rain reaches the hills during 10:00-16:00.

Cloud-free timing: Cloudy early, clearing later.

A wild day on Allt-Fawr: summit wind broadly 30-45 mph, with gusts 50-60 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. Confidence moderate (Summit wind could be roughly 34-50 mph, which changes how difficult exposed walking may feel) - the summit peak could reasonably be 34-50 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.

Medium confidence
Wind26 mph W Gusts36 mph Feels4°C Rain1.4 mm Cloud-free summit86% Cloud base1,574 m Freezing level1,722 m Daylight06:25–20:05 · 13.7 h

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 Allt-Fawr: summit wind broadly 20-30 mph, with gusts 30-40 mph during the afternoon (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. Confidence moderate (forecast models agree on the walking impact of the wind) - the summit peak could reasonably be 21-30 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 run: 2026-08-27

Stay close to Allt-Fawr.

Choose your dates to see whole-home stays ranked by driving time to useful route starts.

Curated for hill access

Our cottage shortlist.

Selected from our cottage catalogue for practical access to routes around Allt-Fawr. Prices and availability must be confirmed with the provider.

Bryn Marian near Allt-Fawr Cottages.com

Bryn Marian

Blaenau Ffestiniog Sleeps 14 Indicative price £1,116 for 7 nights
View this stay
The Old Foundry Barn near Allt-Fawr Cottages.com

The Old Foundry Barn

Blaenau Ffestiniog Sleeps 6 Indicative price £420 for 7 nights
View this stay
Britannic Chambers Apartment near Allt-Fawr Cottages.com

Britannic Chambers Apartment

Blaenau Ffestiniog Sleeps 6 Indicative price £317 for 7 nights
View this stay

Accommodation links may be affiliate links. Prices and availability must be rechecked with the provider. Catalogue updated 26 August 2026 at 13:05 UTC.

Check live dates

Search exact availability.

Choose a weekend and party size to compare live total prices for a seven-night stay.

Accommodation links are affiliate links. Availability and prices may come from Snaptrip, Cottages.com or Stay22 partners for the dates you choose.

A forecast is part of the decision.

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.