Mountain weather

Mountain weather

Eryri / Snowdonia

Confidence

High for overall theme. Lower for confidence on cloud amounts and clearance of rain during Thursday morning.

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.

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.

Mountain weather forecast

Cloudy to start, then bright skies later.

Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
Weather symbols Fog Cloudy Cloudy Sunny intervals Sunny intervals Cloudy
Chance of
precipitation
(at 800m)
Chance of precipitation
70%
10%
10%
10%
10%
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 NW 31mph knots
NW
31mph
NW 26mph knots
NW
26mph
NW 22mph knots
NW
22mph
NW 21mph knots
NW
21mph
W 19mph knots
W
19mph
W 15mph knots
W
15mph
600m
600m NW 21mph knots
NW
21mph
NW 21mph knots
NW
21mph
NW 18mph knots
NW
18mph
NW 17mph knots
NW
17mph
W 14mph knots
W
14mph
SW 10mph knots
SW
10mph
300m
300m NW 15mph knots
NW
15mph
NW 15mph knots
NW
15mph
NW 14mph knots
NW
14mph
NW 13mph knots
NW
13mph
W 10mph knots
W
10mph
W 5mph knots
W
5mph
Valley
Valley NW 15mph knots
NW
15mph
NW 15mph knots
NW
15mph
NW 14mph knots
NW
14mph
W 13mph knots
W
13mph
W 10mph knots
W
10mph
W 5mph knots
W
5mph

Wind gust

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 37mph 32mph 29mph 27mph 25mph 18mph
600m
600m 26mph 26mph 24mph 22mph 19mph 12mph
300m
300m 23mph 23mph 22mph 21mph 16mph 11mph
Valley
Valley 23mph 23mph 22mph 21mph 16mph 11mph

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 1 degrees Celsius 2 degrees Celsius 4 degrees Celsius 5 degrees Celsius 5 degrees Celsius 5 degrees Celsius
600m
600m 5 degrees Celsius 6 degrees Celsius 8 degrees Celsius 8 degrees Celsius 9 degrees Celsius 9 degrees Celsius
300m
300m 9 degrees Celsius 9 degrees Celsius 11 degrees Celsius 12 degrees Celsius 12 degrees Celsius 12 degrees Celsius
Valley
Valley 10 degrees Celsius 11 degrees Celsius 12 degrees Celsius 13 degrees Celsius 14 degrees Celsius 14 degrees Celsius
Freezing Level Freezing Level
2100m
2000m
1800m
1800m
2000m
1900m

Additional weather information

Meteorologist's view

Poor visibilities at first in hill fog requiring good navigational skills, along with brisk winds. Improving later with UV protection required.

Weather

Widespread low cloud from dawn, with outbreaks of rain quickly clearing south. Skies brightening by mid to late morning with sunny spells developing in the afternoon. Brisk northwesterly winds, these easing during the day.

Chance of cloud-free hill tops

20% during the early morning, then 80% later.

Low cloud and visibility

Low cloud and hill fog first thing as a front clears southwards. Cloud then above summits. Very poor visibility initially, then excellent.

Ground conditions

Please see - https://yrwyddfa.live/

Summit specific forecast