Mountain weather

Mountain weather

Eryri / Snowdonia

Confidence

High confidence for a remarkably hot and humid spell of weather between Wednesday and Sunday. Lower confidence for potential severe thunderstorm development late Thursday and on Friday.

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.

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.

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

Exceptionally hot and humid again with prolonged strong sunshine. Risk of thunderstorms overnight.

Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
Weather symbols Sunny Sunny Sunny Sunny Sunny Partly cloudy (night)
Chance of
precipitation
(at 800m)
Chance of precipitation
10%
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 SE 14mph knots
SE
14mph
SE 18mph knots
SE
18mph
SE 19mph knots
SE
19mph
SE 23mph knots
SE
23mph
SE 22mph knots
SE
22mph
SE 32mph knots
SE
32mph
600m
600m SE 13mph knots
SE
13mph
SE 13mph knots
SE
13mph
SE 14mph knots
SE
14mph
SE 17mph knots
SE
17mph
SE 16mph knots
SE
16mph
SE 19mph knots
SE
19mph
300m
300m SE 9mph knots
SE
9mph
SE 11mph knots
SE
11mph
SE 12mph knots
SE
12mph
SE 13mph knots
SE
13mph
SE 11mph knots
SE
11mph
SE 12mph knots
SE
12mph
Valley
Valley SE 9mph knots
SE
9mph
SE 11mph knots
SE
11mph
SE 12mph knots
SE
12mph
SE 13mph knots
SE
13mph
SE 10mph knots
SE
10mph
SE 12mph knots
SE
12mph

Wind gust

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 19mph 22mph 24mph 29mph 27mph 38mph
600m
600m 20mph 17mph 19mph 23mph 21mph 27mph
300m
300m 19mph 17mph 18mph 21mph 19mph 25mph
Valley
Valley 19mph 17mph 18mph 21mph 19mph 25mph

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 20 degrees Celsius 18 degrees Celsius 19 degrees Celsius 20 degrees Celsius 21 degrees Celsius 16 degrees Celsius
600m
600m 22 degrees Celsius 23 degrees Celsius 24 degrees Celsius 25 degrees Celsius 26 degrees Celsius 23 degrees Celsius
300m
300m 24 degrees Celsius 26 degrees Celsius 28 degrees Celsius 29 degrees Celsius 30 degrees Celsius 27 degrees Celsius
Valley
Valley 24 degrees Celsius 28 degrees Celsius 30 degrees Celsius 31 degrees Celsius 32 degrees Celsius 28 degrees Celsius
Freezing Level Freezing Level
3900m
3800m
3900m
3600m
3500m
3500m

Additional weather information

Meteorologist's view

Very hot and humid conditions are expected so carry plenty of water and use adequate sun protection. Stay up to date with Met Office warnings for extreme heat. There is a risk of thunderstorms developing later, bringing frequent lightning and strong, gusty winds, creating potentially dangerous conditions on exposed terrain.

Weather

Dry with some patchy valley mist possible around dawn. Any early mist quickly clearing to leave a sunny and very hot, humid day. Breezier than on Wednesday, with strengthening winds through the day, especially over higher peaks and fells. Overnight, increasing amounts of medium level cloud which brings the risk of showers and thundery downpours.

Chance of cloud-free hill tops

100 %

Low cloud and visibility

No low cloud expected. Some patchy valley mist early daytime, otherwise a rather hazy start with visibilities becoming very good by mid-late morning.

Ground conditions

Please see - https://yrwyddfa.live/

Summit specific forecast