Mountain weather

Eryri / Snowdonia

Eryri / Snowdonia Mountain weather forecast table

Confidence

High for the mobile nature of the westerly weather patterns, but lowering for the transitional timing detail.

Sunrise:
Sunset:

This evening forecast

Occasional clear spells and showers, these wintry across highest peaks. Strong summit winds. Freezing level above summits.

Sunrise:
Sunset:
Mountain hazards

Mountain weather hazards

Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.

hazard Poor Visibility
Poor visibility presents challenging route finding conditions. Visibility could be significantly less than 50 metres in all directions with few or no visual references, especially on featureless moors or plateaux. Distances become hard to judge and cliff or cornice edges can be difficult to recognise. These conditions require good navigational skills. There is a risk of white-out conditions when mist or fog is combined with extensive snow cover.

hazard Gales
Gale force winds (gusts over 50mph) make walking difficult and strenuous with a potential to be blown over by gusts. There is often a marked increase in winds through cols or on exposed ridges and summits. Distances can take longer to cover and compass bearings become harder to follow accurately.
hazard Severe Chill Effect
Wind significantly lowers the ‘feels-like’ temperature relative to the actual temperature, with even moderate winds significantly adding to the chilling effect. Strong winds can result in a severe and debilitating wind chill many degrees below the actual temperature. This effect will be enhanced in rain or wet snow. Without protection, prolonged exposure could result in frost nip or frostbite on exposed parts of the body and/or hypothermia.

Mountain weather forecast

Cloudy with patchy rain by day. Summit gales developing from late morning.

Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
Light rain Cloudy Sleet Light rain Light rain Light rain Light rain Heavy rain
Chance of precipitation
(at 800m)
40% 20% 60% 30% 40% 80% 70% >95%

Wind direction and speed (mph)
Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m SW
25
SW
29
SW
33
S
37
S
40
S
47
S
50
S
48
600m SW
16
SW
18
S
21
S
25
S
29
S
33
S
33
S
32
300m SW
10
SW
10
S
13
S
17
S
20
S
22
S
22
S
22
Valley SW
9
SW
10
S
12
S
17
S
19
S
21
S
21
S
21
Wind gust (mph)
Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m 29 34 40 45 49 57 61 59
600m 21 23 28 32 37 42 43 42
300m 19 21 25 30 34 38 38 39
Valley 19 20 24 30 34 37 38 38

Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m
600m
300m
Valley
Freezing Level
1,100m
900m
900m
1,200m
1,400m
1,600m
1,700m
1,900m

Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m
-5°
-6°
-8°
-7°
-6°
-5°
-5°
-4°
600m
-1°
-2°
-3°
-3°
-2°
-1°
-1°
300m
Valley

Additional weather information

Meteorologist's view

Quite extensive hill fog bringing significant navigational challenges. Severe wind chill extending to mid-levels.

Weather

A cloudy day with patchy light rain developing, with occasional snow across highest peaks through to mid-morning. Outbreaks most persistent across the western areas of the park and during the afternoon. Band of occasionally heavy rain reaching from the west during the evening.

Chance of cloud-free hill tops

10-20%

Low cloud and visibility

Good or very good becoming moderate or poor in rain, very poor within cloud, which will be quite extensive from 500m.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

Most staying dry with only a few well scattered showers crossing the Park, most of these expected during the afternoon. Strong to gale west to southwest summit winds bringing a severe wind chill at height. Freezing level above summits.

Chance of cloud-free hill tops

75%

Maximum wind speed expected

West to southwest mean 35mph, with gusts reaching 50mph across more exposed ridges and summits.

Temperature

  • At 800m Plus 2 Celsius increasing 4 Celsius for the afternoon
  • Valley Plus 6 Celsius increasing 11 Celsius for the afternoon
  • Freezing level 1000m at dawn lifting above summits during the morning

Low cloud and visibility

Good or very good becoming moderate or poor in showers, very poor within cloud, which will occasionally lower to 600m.

Mountain weather information

Thu 12 Mar

Sunrise:
Sunset:

Rather cloudy with frequent showers or longer periods of rain, and later summit snow, that turns heavy at times. Strong to gale force summit winds.

Fri 13 Mar

Sunrise:
Sunset:

Frequent showers, heavy at times with the risk of thunderstorms, with snow level lowering to around 600m. Strong summit winds bringing severe wind chill at height. Freezing level 700m.

Sat 14 Mar

Sunrise:
Sunset:

Rather cloudy with some patchy light rain. Strong summit winds.

Updated at:

Summit specific forecast

Mountain summit forecast map

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