Mountain weather

Eryri / Snowdonia

Eryri / Snowdonia Mountain weather forecast table

Confidence

High for unsettled conditions with rain spreading in from the south and west at times. Confidence in the day-to-day detail decreasing through the period so please keep updated on the forecast.

Sunrise:
Sunset:

This evening forecast

Mainly dry with clear spells but some areas of mist and fog developing. Fresh southerly winds on the tops. 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 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

Outbreaks of rain and summit sleet or snow. Cold and breezy on the tops.

Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
Cloudy Fog Fog Fog Sleet Sleet Cloudy Sleet
Chance of precipitation
(at 800m)
<05% <05% <05% 10% 70% 90% 90% 90%

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 SE
17
SE
16
SE
18
SE
18
SE
16
S
12
SE
12
SE
12
600m SE
12
SE
12
SE
12
SE
11
SE
11
S
9
SE
8
SE
8
300m SE
9
SE
9
SE
9
SE
7
SE
6
SE
5
SE
4
SE
4
Valley SE
10
SE
10
SE
10
SE
8
SE
7
SE
5
SE
5
SE
4
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 21 20 22 22 19 15 14 15
600m 16 16 17 16 15 12 11 11
300m 15 15 15 14 11 9 8 7
Valley 17 17 16 15 12 8 8 7

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
1,000m
1,000m
1,000m
1,100m
1,100m
1,100m
1,100m
1,100m

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

Additional weather information

Meteorologist's view

A cold day on the tops with a significant wind chill, especially in rain and sleet. Difficult navigation conditions as low cloud becomes extensive.

Weather

Mainly dry overnight with areas of low cloud. Sunday starts off mostly dry with some low cloud, best of any brightness over lower northern hills. Outbreaks of rain will soon spread northwards, becoming heavy at times with some sleet or snow above 800m.

Chance of cloud-free hill tops

10%.

Low cloud and visibility

Extensive cloud with bases 300-500m, but higher at times over far northern hills. Away from low cloud, visibility rather hazy and often dropping to a few kilometres in rain or sleet.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

Low cloud with outbreaks of rain through the day and overnight. Some sleet above 900m with a significant wind chill on the tops.

Chance of cloud-free hill tops

Less than 10%.

Maximum wind speed expected

Southeast 20mph gusts 30mph.

Temperature

  • At 800m Plus 2C.
  • Valley Plus 6 or 7C.
  • Freezing level Above summits.

Low cloud and visibility

Extensive cloud and fog above 300 or 400m, lifting to 600m at times over northern hills. Some good visibility at times below the cloud base.

Mountain weather information

Tue 20 Jan

Sunrise:
Sunset:

Low cloud with outbreaks of rain at first then becoming drier and brighter for a period. Further heavy rain and summit snow is likely to arrive in the evening. Strong southerly winds with a severe wind chill on the tops. Freezing level above summits.

Wed 21 Jan

Sunrise:
Sunset:

Outbreaks of rain, heavy at times with sleet or snow on high summits. Severe gale force southerly winds with severe wind chill on the tops. Freezing level 900m then rising above summits.

Thu 22 Jan

Sunrise:
Sunset:

It is expected to remain unsettled and very windy with further periods of rain. Severe gale force southerly winds. Freezing level above summits.

Updated at:

Summit specific forecast

Mountain summit forecast map

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