Mountain weather

Mountain weather

Eryri / Snowdonia

Confidence

High for overall story, moderate for shower detail through Wednesday and lower Friday into Saturday.

Mountain hazards

Mountain weather hazards

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

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.
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.

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.
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

Isolated light showers with areas of low level cloud around. Windy.

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

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 SW 35mph knots
SW
35mph
SW 32mph knots
SW
32mph
SW 29mph knots
SW
29mph
SW 27mph knots
SW
27mph
SW 28mph knots
SW
28mph
SW 31mph knots
SW
31mph
600m
600m SW 23mph knots
SW
23mph
SW 22mph knots
SW
22mph
SW 22mph knots
SW
22mph
SW 21mph knots
SW
21mph
SW 19mph knots
SW
19mph
SW 21mph knots
SW
21mph
300m
300m SW 14mph knots
SW
14mph
SW 14mph knots
SW
14mph
SW 16mph knots
SW
16mph
SW 15mph knots
SW
15mph
SW 13mph knots
SW
13mph
SW 14mph knots
SW
14mph
Valley
Valley SW 13mph knots
SW
13mph
SW 14mph knots
SW
14mph
SW 16mph knots
SW
16mph
SW 15mph knots
SW
15mph
SW 12mph knots
SW
12mph
S 15mph knots
S
15mph

Wind gust

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 41mph 39mph 36mph 34mph 35mph 38mph
600m
600m 29mph 29mph 29mph 28mph 25mph 28mph
300m
300m 25mph 26mph 28mph 26mph 22mph 25mph
Valley
Valley 25mph 25mph 27mph 26mph 21mph 26mph

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m -2 degrees Celsius 0 degrees Celsius 1 degrees Celsius 3 degrees Celsius 3 degrees Celsius 0 degrees Celsius
600m
600m 2 degrees Celsius 4 degrees Celsius 5 degrees Celsius 6 degrees Celsius 6 degrees Celsius 4 degrees Celsius
300m
300m 7 degrees Celsius 8 degrees Celsius 9 degrees Celsius 11 degrees Celsius 9 degrees Celsius 7 degrees Celsius
Valley
Valley 8 degrees Celsius 10 degrees Celsius 11 degrees Celsius 12 degrees Celsius 11 degrees Celsius 9 degrees Celsius
Freezing Level Freezing Level
1700m
1900m
2000m
2100m
2300m
1900m

Additional weather information

Meteorologist's view

Feeling chilly in the strong winds, which may reach 50mph on highest ridges and summits, making for difficult walking conditions. Poor navigation conditions during the morning, although this is expected to improve briefly, conditions are likely to deteriorate again during the afternoon. Despite this, Moderate UV levels are possible in any brighter spells, so sun protection should be considered.

Weather

Cloudy with scattered light to moderate showers at first. Showers turning more isolated and lighter through the morning, perhaps with some brighter spells developing, before cloud begins to thicken from the south through the late afternoon, this may allow for the odd spot of light rain to develop. Windy, especially on higher slopes.

Chance of cloud-free hill tops

30% at first, rising to 60% from late morning, then dropping to 40% from late afternoon onwards.

Low cloud and visibility

Widespread cloud initially above 400-600m, main cloud layer will then rise to 600-800m, with patchy cloud above 500m. From late afternoon areas of cloud with base 400-500m. Good to very good visibility outside any low cloud or showers, visibility turning moderate to very poor in any showers or hill fog.

Ground conditions

Please see - https://yrwyddfa.live/

Summit specific forecast