Mountain weather

Mountain weather

Eryri / Snowdonia

Confidence

Moderate for rain details on Wednesday. Low for timings of strongest winds and rain on Thursday and Friday.

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.

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.

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.
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.

Mountain weather forecast

Heavy rain slowly easing but staying damp and blustery with drizzle at times.

Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
Weather symbols Light rain Heavy Rain Heavy Rain Fog Fog Drizzle
Chance of
precipitation
(at 800m)
Chance of precipitation
70%
90%
60%
50%
30%
30%

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 S 26mph knots
S
26mph
S 37mph knots
S
37mph
SW 33mph knots
SW
33mph
SW 26mph knots
SW
26mph
SW 28mph knots
SW
28mph
SW 30mph knots
SW
30mph
600m
600m S 19mph knots
S
19mph
S 24mph knots
S
24mph
SW 23mph knots
SW
23mph
SW 19mph knots
SW
19mph
SW 18mph knots
SW
18mph
SW 18mph knots
SW
18mph
300m
300m S 11mph knots
S
11mph
S 14mph knots
S
14mph
SW 15mph knots
SW
15mph
SW 12mph knots
SW
12mph
SW 11mph knots
SW
11mph
SW 11mph knots
SW
11mph
Valley
Valley S 11mph knots
S
11mph
S 14mph knots
S
14mph
SW 15mph knots
SW
15mph
SW 12mph knots
SW
12mph
SW 11mph knots
SW
11mph
SW 11mph knots
SW
11mph

Wind gust

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 30mph 43mph 40mph 33mph 35mph 36mph
600m
600m 24mph 29mph 30mph 25mph 23mph 24mph
300m
300m 22mph 27mph 28mph 22mph 22mph 23mph
Valley
Valley 22mph 26mph 26mph 21mph 22mph 22mph

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 7 degrees Celsius 6 degrees Celsius 8 degrees Celsius 9 degrees Celsius 8 degrees Celsius 8 degrees Celsius
600m
600m 9 degrees Celsius 9 degrees Celsius 11 degrees Celsius 12 degrees Celsius 12 degrees Celsius 12 degrees Celsius
300m
300m 12 degrees Celsius 13 degrees Celsius 14 degrees Celsius 15 degrees Celsius 15 degrees Celsius 15 degrees Celsius
Valley
Valley 14 degrees Celsius 14 degrees Celsius 16 degrees Celsius 17 degrees Celsius 17 degrees Celsius 16 degrees Celsius
Freezing Level Freezing Level
2900m
3200m
3000m
3000m
3100m
3000m

Additional weather information

Meteorologist's view

Challenging navigation on the hills, with heavy rain at times bringing a risk of waterproofs becoming soaked and slippery ground underfoot. Strong winds may make for arduous walking on exposed terrain.

Weather

Increasingly wet through the morning hours, with heavy rain developing. The rain will be prolonged but showery in nature, with occasional drier spells developing through the afternoon and a few glimmers of sunshine possible in eastern areas during the evening.

Chance of cloud-free hill tops

10%, becoming 30% east.

Low cloud and visibility

Persistent and extensive cloud above 300-400m (400-600m in the east). This will give widespread fog and reduce visibility to poor or very poor. Occasional poor or very poor visibility at valley level too in periods of rain and drizzle but tending to become mostly good or very good visibility at lower levels later in the day.

Ground conditions

Please see - https://yrwyddfa.live/

Summit specific forecast