Mountain weather

Mountain weather

Eryri / Snowdonia

Confidence

High for overall evolution but lower for details of low cloud and location of heaviest rain and showers throughout.

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.

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.

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

A cloudy day ahead with patchy rain and showers.

Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
Weather symbols Light rain Light rain Cloudy Cloudy Drizzle Heavy Rain
Chance of
precipitation
(at 800m)
Chance of precipitation
40%
40%
20%
20%
40%
40%

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 SW 21mph knots
SW
21mph
SW 26mph knots
SW
26mph
SW 30mph knots
SW
30mph
SW 34mph knots
SW
34mph
SW 32mph knots
SW
32mph
SW 37mph knots
SW
37mph
600m
600m S 15mph knots
S
15mph
SW 20mph knots
SW
20mph
SW 23mph knots
SW
23mph
SW 23mph knots
SW
23mph
S 22mph knots
S
22mph
SW 25mph knots
SW
25mph
300m
300m S 8mph knots
S
8mph
SW 11mph knots
SW
11mph
SW 16mph knots
SW
16mph
S 17mph knots
S
17mph
S 15mph knots
S
15mph
S 16mph knots
S
16mph
Valley
Valley S 7mph knots
S
7mph
SW 11mph knots
SW
11mph
SW 15mph knots
SW
15mph
S 17mph knots
S
17mph
S 15mph knots
S
15mph
S 15mph knots
S
15mph

Wind gust

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 25mph 32mph 38mph 42mph 39mph 45mph
600m
600m 19mph 25mph 31mph 31mph 30mph 33mph
300m
300m 14mph 19mph 27mph 28mph 27mph 30mph
Valley
Valley 14mph 19mph 26mph 28mph 27mph 28mph

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 9 degrees Celsius 9 degrees Celsius 8 degrees Celsius 7 degrees Celsius 7 degrees Celsius 7 degrees Celsius
600m
600m 11 degrees Celsius 12 degrees Celsius 10 degrees Celsius 10 degrees Celsius 10 degrees Celsius 10 degrees Celsius
300m
300m 14 degrees Celsius 15 degrees Celsius 14 degrees Celsius 13 degrees Celsius 13 degrees Celsius 13 degrees Celsius
Valley
Valley 16 degrees Celsius 16 degrees Celsius 16 degrees Celsius 15 degrees Celsius 15 degrees Celsius 15 degrees Celsius
Freezing Level Freezing Level
3700m
3200m
3800m
3400m
3300m
3400m

Additional weather information

Meteorologist's view

Low cloud and poor visibilities will make navigation challenging.

Weather

A cloudy day ahead with outbreaks of light and patchy rain possible throughout the day, some of this rain may turn heavy around dawn. Cloud may lift somewhat through the afternoon to allow for the odd brighter spell. Moderate southwesterly wind.

Chance of cloud-free hill tops

<10% through the morning rising to 40% through the afternoon before dropping to <10% once again.

Low cloud and visibility

Extensive low cloud initially between 300-400m. Through the morning cloud bases lifting to 600-800m, with some patchier cloud at 500m. Cloud bases then gradually lowering again into the evening. Generally poor to very poor visibility in rain and low cloud, but good outside of low cloud.

Ground conditions

No recent ground conditions report available.

Summit specific forecast