Mountain weather

Mountain weather

Eryri / Snowdonia

Confidence

High confidence for a continuation of changeable conditions but lower confidence for cloud and rainfall detail, and timing of rain/shower bands.

Mountain hazards

Mountain weather hazards

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

Strong Sunlight
Harmful UV levels from sunlight increase with altitude giving a greater risk of sunburn and eye damage, even on some overcast days. On breezy days, the cooling effect of wind on exposed skin may disguise any feeling of sunburn until it is too late. If there is snow cover, glare increases the effect of UV rays especially on the eyes. It is advisable to wear sun block, protective clothing such as a long-sleeved top and hat and have good quality eye protection.

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.
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.
Thunderstorms
Lightning is a significant mountain hazard which can result in serious injury or death. Mountain terrain often leaves one highly exposed to lightning strikes. Hail may give unpleasant conditions with torrential rain and localised flash flooding also possible, mainly in Summer months.

Mountain weather forecast

Rain clearing to sunny spells and isolated showers.

Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
Weather symbols Fog Cloudy Sunny intervals Sunny intervals Sunny intervals Heavy rain showers
Chance of
precipitation
(at 800m)
Chance of precipitation
30%
10%
10%
10%
20%
30%

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 NW 20mph knots
NW
20mph
W 18mph knots
W
18mph
W 20mph knots
W
20mph
W 23mph knots
W
23mph
SW 25mph knots
SW
25mph
SW 29mph knots
SW
29mph
600m
600m NW 13mph knots
NW
13mph
W 14mph knots
W
14mph
W 16mph knots
W
16mph
W 18mph knots
W
18mph
SW 19mph knots
SW
19mph
SW 18mph knots
SW
18mph
300m
300m NW 9mph knots
NW
9mph
W 11mph knots
W
11mph
W 12mph knots
W
12mph
W 13mph knots
W
13mph
SW 13mph knots
SW
13mph
SW 11mph knots
SW
11mph
Valley
Valley NW 9mph knots
NW
9mph
W 11mph knots
W
11mph
W 12mph knots
W
12mph
W 13mph knots
W
13mph
SW 13mph knots
SW
13mph
SW 10mph knots
SW
10mph

Wind gust

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 24mph 23mph 26mph 29mph 32mph 35mph
600m
600m 17mph 19mph 21mph 24mph 25mph 24mph
300m
300m 16mph 17mph 19mph 22mph 23mph 20mph
Valley
Valley 16mph 18mph 19mph 21mph 22mph 20mph

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m -1 degrees Celsius -1 degrees Celsius -1 degrees Celsius 0 degrees Celsius -1 degrees Celsius -2 degrees Celsius
600m
600m 3 degrees Celsius 3 degrees Celsius 3 degrees Celsius 4 degrees Celsius 3 degrees Celsius 2 degrees Celsius
300m
300m 6 degrees Celsius 7 degrees Celsius 8 degrees Celsius 8 degrees Celsius 8 degrees Celsius 6 degrees Celsius
Valley
Valley 8 degrees Celsius 9 degrees Celsius 10 degrees Celsius 10 degrees Celsius 10 degrees Celsius 8 degrees Celsius
Freezing Level Freezing Level
1500m
1300m
1200m
1300m
1500m
1500m

Additional weather information

Meteorologist's view

Slippery surfaces at first after overnight rain. A day for layers. Sun protection is recommended for the afternoon hours, as UV levels will be moderate or high, however feeling cold especially on the higher slopes in the wind.

Weather

Heavy overnight rain clearing to the east around dawn, with brighter conditions following but also isolated showers. More in the way of sunny spells developing for the afternoon, with any showers easing. However, further blustery showers arrive during the evening, these locally heavy and perhaps thundery.

Chance of cloud-free hill tops

40% rising to 90% by mid to late morning.

Low cloud and visibility

Areas of cloud, bases down to 400-500m at first, lifting above the summits by mid to late morning. Briefly lowering again in any showers during the evening. Visibility will be moderate to very poor in low cloud and rain first thing, soon improving to good or very good, but briefly moderate to poor in any showers.

Ground conditions

Please see - https://yrwyddfa.live/

Summit specific forecast