Mountain weather

Mountain weather

Eryri / Snowdonia

Confidence

High for a very unsettled and occasionally stormy period of weather. Lower for exact detail and timing of each weather system.

Sunrise: Sunset:
Sunrise: Sunset:
Mountain hazards

Mountain weather hazards

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

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.
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.
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.

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.

Blizzards
Blizzards and whiteouts present challenging and serious conditions due to a combination of falling or blowing snow, strong winds and cold temperatures. They can be highly disorientating, often resulting in near-zero visibility with limited or no visual references and no distinction between ground and sky. Cliff edges and cornices may not be apparent, even close up. These conditions require very good navigational skills.
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.

Mountain weather forecast

Periods of heavy rain, turning to snow on the tops. Severe gales at height and feeling cold.

Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
Weather symbols Light rain Heavy Rain Heavy Rain Sleet Sleet Partly cloudy (night)
Chance of
precipitation
(at 800m)
Chance of precipitation
30%
50%
60%
50%
30%
10%

Wind direction and speed

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m W 31mph knots
W
31mph
W 34mph knots
W
34mph
W 38mph knots
W
38mph
W 39mph knots
W
39mph
W 38mph knots
W
38mph
W 36mph knots
W
36mph
600m
600m W 21mph knots
W
21mph
W 24mph knots
W
24mph
W 27mph knots
W
27mph
W 27mph knots
W
27mph
W 26mph knots
W
26mph
W 24mph knots
W
24mph
300m
300m W 18mph knots
W
18mph
W 21mph knots
W
21mph
W 24mph knots
W
24mph
W 24mph knots
W
24mph
W 22mph knots
W
22mph
W 20mph knots
W
20mph
Valley
Valley W 16mph knots
W
16mph
W 20mph knots
W
20mph
W 23mph knots
W
23mph
W 22mph knots
W
22mph
W 19mph knots
W
19mph
W 18mph knots
W
18mph

Wind gust

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 45mph 51mph 57mph 57mph 54mph 50mph
600m
600m 35mph 41mph 46mph 45mph 41mph 38mph
300m
300m 32mph 37mph 42mph 41mph 38mph 34mph
Valley
Valley 29mph 37mph 41mph 39mph 34mph 31mph

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m -4 degrees Celsius -6 degrees Celsius -6 degrees Celsius -6 degrees Celsius -7 degrees Celsius -8 degrees Celsius
600m
600m 0 degrees Celsius -2 degrees Celsius -2 degrees Celsius -2 degrees Celsius -3 degrees Celsius -3 degrees Celsius
300m
300m 3 degrees Celsius 2 degrees Celsius 1 degrees Celsius 2 degrees Celsius 1 degrees Celsius 1 degrees Celsius
Valley
Valley 5 degrees Celsius 4 degrees Celsius 4 degrees Celsius 4 degrees Celsius 3 degrees Celsius 3 degrees Celsius
Freezing Level Freezing Level
1600m
1200m
1000m
1000m
1000m
900m

Additional weather information

Meteorologist's view

Very strong west or northwest winds with gusts of 60mph on high slopes and ridges giving a high risk of being blown over. Also feeling very cold with a significant wind chill on the tops and possible blizzard conditions.

Weather

Heavy rain clearing in the early hours then drier for a time, then rain will return in the morning, becoming heavy at times. Rain will turn to sleet or snow above 800m from late morning onwards with a chance of blizzard conditions on the highest tops. Becoming dry in the evening.

Chance of cloud-free hill tops

20%, becoming 80% in evening.

Low cloud and visibility

Visibility often poor in rain or summit snow with frequent cloud above 600 or 700m. Blizzard conditions may bring some particularly difficult navigation conditions in the afternoon on highest tops. Cloud lifting in the evening.

Ground conditions

No recent ground conditions report available.

Summit specific forecast