Mountain weather

Mountain weather

Eryri / Snowdonia

Confidence

High for a showery couple of days. Low for the chance of any thunderstorms.

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.

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.
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.
Heavy Persistent Rain
Heavy and persistent rain can lead to drenched clothing and footwear with waterproofs often becoming soaked through, especially if accompanied by strong winds. This can lead to significant loss of body heat and an increased likelihood of hypothermia. Terrain may turn increasingly boggy underfoot while streams can flood and become impassable. There may also be a risk of flooding in valleys or glens. If there is snow cover, a heightened avalanche hazard is possible and avalanche reports should be consulted where available.

Mountain weather forecast

Sunshine and showers.

Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
Weather symbols Fog Light rain showers Light rain showers Heavy rain showers Heavy rain showers Light rain showers (night)
Chance of
precipitation
(at 800m)
Chance of precipitation
40%
60%
60%
70%
70%
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 W 27mph knots
W
27mph
W 28mph knots
W
28mph
W 30mph knots
W
30mph
W 29mph knots
W
29mph
W 23mph knots
W
23mph
W 22mph knots
W
22mph
600m
600m W 19mph knots
W
19mph
W 22mph knots
W
22mph
W 22mph knots
W
22mph
W 22mph knots
W
22mph
W 16mph knots
W
16mph
W 13mph knots
W
13mph
300m
300m W 13mph knots
W
13mph
W 16mph knots
W
16mph
W 17mph knots
W
17mph
W 15mph knots
W
15mph
W 11mph knots
W
11mph
SW 9mph knots
SW
9mph
Valley
Valley W 13mph knots
W
13mph
W 16mph knots
W
16mph
W 17mph knots
W
17mph
W 15mph knots
W
15mph
W 11mph knots
W
11mph
SW 9mph knots
SW
9mph

Wind gust

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 33mph 35mph 38mph 37mph 29mph 26mph
600m
600m 24mph 28mph 30mph 30mph 22mph 18mph
300m
300m 21mph 26mph 28mph 26mph 19mph 16mph
Valley
Valley 21mph 26mph 28mph 26mph 19mph 16mph

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 -2 degrees Celsius -1 degrees Celsius -1 degrees Celsius -2 degrees Celsius
600m
600m 1 degrees Celsius 1 degrees Celsius 2 degrees Celsius 3 degrees Celsius 3 degrees Celsius 2 degrees Celsius
300m
300m 5 degrees Celsius 5 degrees Celsius 7 degrees Celsius 7 degrees Celsius 7 degrees Celsius 6 degrees Celsius
Valley
Valley 7 degrees Celsius 7 degrees Celsius 8 degrees Celsius 9 degrees Celsius 9 degrees Celsius 8 degrees Celsius
Freezing Level Freezing Level
1200m
1300m
1300m
1400m
1400m
1400m

Additional weather information

Meteorologist's view

Conditions could change quickly throughout the day so keep waterproofs on hand. Also remember that UV levels will be high when the sunshine does emerge, despite the brisk wind making it feel chilly.

Weather

Early morning mist or low cloud will soon lift to give some bright or sunny spells. However, the clouds will bubble up to give a mixture of sunny spells and showers during the afternoon. Some of the showers are likely to be heavy, with the risk of hail and thunder at times. The showers are likely to continue into the evening.

Chance of cloud-free hill tops

70%

Low cloud and visibility

Cloud bases periodically down to 500-600m first thing and in showers, otherwise, above the summits. Visibility will generally be good, but reducing to moderate or poor in showers.

Ground conditions

Please see - https://yrwyddfa.live/

Summit specific forecast