Mountain weather

Eryri / Snowdonia

Yellow warning

Yellow weather warning in force for Eryri / Snowdonia

Eryri / Snowdonia Mountain weather forecast table

Confidence

High, but Medium for rainfall details on Monday.

Sunrise:
Sunset:

This evening forecast

Strengthening SW winds, lowering cloud and outbreaks of rain.

Sunrise:
Sunset:
Mountain hazards

Mountain weather hazards

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

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 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 Storm Force Winds
Storm force winds (gusts over 70mph) make walking very strenuous with any mobility virtually impossible over exposed ground. Where these conditions occur there is a high risk of being blown over and even standing may be impossible at times with a risk of being blown off one’s feet. Basic tasks such as using a map, eating, putting on extra clothing or communication become extremely difficult away from any shelter.
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.
hazard Heavy Persistent Rain
Heavy and persistent rain can lead to drenched clothing and footwear with waterproofs often becoming soaked through, especially if accompanied by strong winds. This can lead to significant loss of body heat and an increased likelihood of hypothermia. Terrain may turn increasingly boggy underfoot while streams can flood and become impassable. There may also be a risk of flooding in valleys or glens. If there is snow cover, a heightened avalanche hazard is possible and avalanche reports should be consulted where available.

Mountain weather forecast

Wet and very windy. Gale or storm force summit winds.

Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
Light rain Heavy rain Light rain Light rain Heavy rain Heavy rain Heavy rain Heavy rain
Chance of precipitation
(at 800m)
70% 90% 80% 80% 80% 80% 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 SW
58
SW
58
S
54
S
56
S
62
S
60
S
61
S
58
600m S
38
S
39
S
37
S
39
S
43
S
42
S
43
S
41
300m S
24
S
24
S
23
S
24
S
27
S
27
S
27
S
25
Valley S
24
S
24
S
23
S
25
S
27
S
27
S
27
S
26
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 69 69 65 67 74 73 75 71
600m 48 49 47 50 55 55 56 53
300m 42 42 41 43 48 47 48 46
Valley 42 42 41 44 48 48 49 46

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
10°
10°
10°
Freezing Level
2,500m
2,900m
2,900m
2,900m
3,000m
2,900m
2,800m
2,600m

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

Additional weather information

Meteorologist's view

A poor day across the park with hazardous conditions.

Weather

Cloudy and overcast with outbreaks of rain, heavy and persistent at times. Buffeting at height along with poor or very poor visibility. Some flooding possible.

Chance of cloud-free hill tops

10%

Low cloud and visibility

Extensive low cloud base 300 to 600m. Visibility moderate to very poor.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

Further heavy and persistent rain overnight and through daylight hours with a continuing flooding risk. The rain should turn lighter and patchy during the evening.

Chance of cloud-free hill tops

10% becoming 60% in the evening.

Maximum wind speed expected

South or Southwest 25 to 35mph gusting 50mph, easing at times.

Temperature

  • At 800m Plus 2 to 5 Celsius
  • Valley Plus 6 to 10 Celsius
  • Freezing level Above the summits

Low cloud and visibility

Extensive low cloud base 300 to 500m, tending to lift and break late in the day. Visibility moderate to very poor, improving late in the day.

Mountain weather information

Tue 16 Dec

Sunrise:
Sunset:

Dry and bright with some sunny or clear spells. Frost and valley fog or freezing fog possible. Light or moderate west or northwest, becoming southwest, winds at height. Freezing level well down early and late, but rising towards the summits by day.

Wed 17 Dec

Sunrise:
Sunset:

Lowering cloud with outbreaks of rain, heavy at times. South or southwest winds becoming strong to gale force at height.

Thu 18 Dec

Sunrise:
Sunset:

Further heavy and persistent rain possible, but confidence low. Gale force summit winds also possible.

Updated at:

Summit specific forecast

Mountain summit forecast map

Loading map…