Mountain weather

Mountain weather

Eryri / Snowdonia

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yellow Warning
Yellow weather warning in force for Eryri / Snowdonia

Confidence

High for the unsettled weather, with spells of strong winds, however the extent of cloud and any wintry precipitation on Friday is lower confidence. High for further periods of wet and very windy weather over the weekend and into the coming week.

Sunrise: Sunset:
Sunrise: Sunset:
Mountain hazards

Mountain weather hazards

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

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.
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.
Updated: 
Mountain hazards explained

Mountain weather forecast

Early rain clearing, then largely fine and dry. Cloud thickening through the evening, with rain possible by midnight.

Time
 Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
 Weather symbols Light rain Light rain Cloudy Sunny intervals Cloudy Light rain
Chance of
precipitation
(at 800m)
 Chance of precipitation
40%
30%
10%
10%
10%
50%

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 W 16mph knots
W
16mph
 SW 16mph knots
SW
16mph
 SW 15mph knots
SW
15mph
 S 16mph knots
S
16mph
 SE 21mph knots
SE
21mph
 SE 30mph knots
SE
30mph
600m
 600m W 11mph knots
W
11mph
 SW 11mph knots
SW
11mph
 SW 12mph knots
SW
12mph
 S 12mph knots
S
12mph
 SE 13mph knots
SE
13mph
 SE 19mph knots
SE
19mph
300m
 300m W 8mph knots
W
8mph
 SW 9mph knots
SW
9mph
 SW 11mph knots
SW
11mph
 S 10mph knots
S
10mph
 SE 10mph knots
SE
10mph
 SE 15mph knots
SE
15mph
Valley
 Valley SW 8mph knots
SW
8mph
 SW 8mph knots
SW
8mph
 SW 10mph knots
SW
10mph
 S 9mph knots
S
9mph
 SE 8mph knots
SE
8mph
 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 23mph 24mph 25mph 24mph 28mph 42mph
600m
 600m 17mph 19mph 22mph 20mph 21mph 31mph
300m
 300m 14mph 15mph 21mph 19mph 16mph 25mph
Valley
 Valley 14mph 15mph 19mph 17mph 14mph 21mph

Altitude above mean sea level
Time
 Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
 900m -4 degrees Celsius -3 degrees Celsius 0 degrees Celsius 0 degrees Celsius -2 degrees Celsius -3 degrees Celsius
600m
 600m -1 degrees Celsius 1 degrees Celsius 4 degrees Celsius 4 degrees Celsius 2 degrees Celsius 1 degrees Celsius
300m
 300m 2 degrees Celsius 4 degrees Celsius 7 degrees Celsius 7 degrees Celsius 4 degrees Celsius 4 degrees Celsius
Valley
 Valley 4 degrees Celsius 6 degrees Celsius 9 degrees Celsius 9 degrees Celsius 6 degrees Celsius 6 degrees Celsius
Freezing Level Freezing Level
1200m
1200m
1200m
1300m
1400m
1800m

Additional weather information

Meteorologist's view

While freezing levels will remain above the summits, blustery winds will lead to it feeling below freezing on the summits, with warm layers essential. Waterproofs will also be needed, especially with the chance of rain spreading in later.

Weather

Cloudy start with some rain, but this soon clearing from all tops. Then staying dry through the afternoon, with some brighter spells. Cloud and winds then increasing early evening, with rain moving into the far southwest towards midnight.

Chance of cloud-free hill tops

30% becoming 90% from late morning. Falling to 20% during evening, and near zero by midnight.

Low cloud and visibility

Cloud will obscure most summits above 800m at first, with a few patches down to 500m in any rain. This lifting and breaking during the morning, with all summits clear by the afternoon. However, cloud will thicken again through the evening, descending to obscure hills from above 600m, with some patches down to 400m. Outside of cloud, visibility will be very good for much of the day, with distant hills visible, but falling to moderate to poor in rain early and late.

Ground conditions

No recent ground conditions report available.

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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