Mountain weather

Mountain weather

Eryri / Snowdonia

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yellow Warning
Yellow weather warning in force for Eryri / Snowdonia

Confidence

High in terms of the overall evolution but low for the timings and extent of showers/thunderstorms.

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.
Updated: 
Mountain hazards explained

Mountain weather forecast

Generally dry, feeling cooler with a chance of thunderstorms in the afternoon.

Time
 Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
 Weather symbols Sunny Sunny Sunny intervals Sunny intervals Thunderstorm Thunderstorm
Chance of
precipitation
(at 800m)
 Chance of precipitation
10%
10%
20%
20%
60%
60%

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 E 13mph knots
E
13mph
 E 15mph knots
E
15mph
 SE 16mph knots
SE
16mph
 SE 18mph knots
SE
18mph
 SE 18mph knots
SE
18mph
 E 24mph knots
E
24mph
600m
 600m SE 13mph knots
SE
13mph
 SE 15mph knots
SE
15mph
 SE 15mph knots
SE
15mph
 SE 14mph knots
SE
14mph
 SE 13mph knots
SE
13mph
 E 19mph knots
E
19mph
300m
 300m SE 10mph knots
SE
10mph
 SE 13mph knots
SE
13mph
 SE 12mph knots
SE
12mph
 SE 12mph knots
SE
12mph
 SE 9mph knots
SE
9mph
 E 14mph knots
E
14mph
Valley
 Valley SE 10mph knots
SE
10mph
 SE 13mph knots
SE
13mph
 SE 12mph knots
SE
12mph
 SE 12mph knots
SE
12mph
 SE 9mph knots
SE
9mph
 E 14mph knots
E
14mph

Wind gust

Altitude above mean sea level
Time
 Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
 900m 17mph 19mph 21mph 23mph 22mph 31mph
600m
 600m 16mph 19mph 19mph 20mph 18mph 29mph
300m
 300m 19mph 18mph 18mph 18mph 17mph 27mph
Valley
 Valley 19mph 18mph 18mph 18mph 17mph 27mph

Altitude above mean sea level
Time
 Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
 900m 14 degrees Celsius 12 degrees Celsius 14 degrees Celsius 14 degrees Celsius 15 degrees Celsius 11 degrees Celsius
600m
 600m 16 degrees Celsius 15 degrees Celsius 17 degrees Celsius 18 degrees Celsius 19 degrees Celsius 14 degrees Celsius
300m
 300m 18 degrees Celsius 18 degrees Celsius 21 degrees Celsius 22 degrees Celsius 22 degrees Celsius 17 degrees Celsius
Valley
 Valley 18 degrees Celsius 19 degrees Celsius 23 degrees Celsius 24 degrees Celsius 23 degrees Celsius 18 degrees Celsius
Freezing Level Freezing Level
2900m
2400m
2900m
3100m
3200m
3200m

Additional weather information

Meteorologist's view

There is a risk of dehydration and heat exhaustion so it is advisable to take plenty of water and take other precautions such as wearing sunhats and seeking shade. The sunny conditions will result in very high UV levels, so remember to protect your skin from the strong sunshine. Winds may gust up to 10 mph higher than the values in the table above over the highest summits and ridges, making for a notably windy day in places. Also be aware that there's a chance of thunderstorms developing later.

Weather

Warm through the early hours and probably remaining dry and clear. Another generally sunny day on Wednesday, with variable cloud and the chance of scattered showers or thunderstorms later in the day, most likely evening onwards. Feeling very warm but not as hot as on Tuesday, partly due to a brisk easterly wind over the summits.

Chance of cloud-free hill tops

Greater than 90%.

Low cloud and visibility

The odd scrap of cloud possible around dawn on east facing slopes in the east of the National Park, around 500m, rapidly clearly after dawn. Generally good visibility but distant hills and landmarks may appear faint or hazy. Poor visibility in any showers or thunderstorms and locally very poor in any cloud/hill fog at first.

Ground conditions

Please see - https://yrwyddfa.live/

Summit specific forecast

The Eryri (Snowdonia) mountains are made up of 90 mountain peaks including the tallest mountain in Wales, Yr Wyddfa (Snowdon), standing at 1,085 metres.

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