Mountain weather

Mountain weather

Eryri / Snowdonia

Confidence

High for a change to much cooler and windier weather by Wednesday. Low for the details of showers and possible thunderstorms over the next 24 hours.

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.

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

Breezy with a chance of rain or showers, possibly heavy in places.

Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
Weather symbols Heavy Rain Heavy Rain Heavy Rain Fog Fog Drizzle
Chance of
precipitation
(at 800m)
Chance of precipitation
60%
60%
50%
40%
30%
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 S 35mph knots
S
35mph
SW 25mph knots
SW
25mph
SW 26mph knots
SW
26mph
SW 30mph knots
SW
30mph
SW 33mph knots
SW
33mph
SW 29mph knots
SW
29mph
600m
600m S 21mph knots
S
21mph
S 19mph knots
S
19mph
SW 19mph knots
SW
19mph
SW 22mph knots
SW
22mph
SW 23mph knots
SW
23mph
SW 21mph knots
SW
21mph
300m
300m S 12mph knots
S
12mph
S 12mph knots
S
12mph
S 13mph knots
S
13mph
SW 15mph knots
SW
15mph
SW 15mph knots
SW
15mph
SW 14mph knots
SW
14mph
Valley
Valley S 13mph knots
S
13mph
S 12mph knots
S
12mph
S 13mph knots
S
13mph
SW 15mph knots
SW
15mph
SW 15mph knots
SW
15mph
SW 13mph knots
SW
13mph

Wind gust

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 40mph 31mph 32mph 38mph 42mph 36mph
600m
600m 26mph 24mph 26mph 29mph 30mph 28mph
300m
300m 23mph 22mph 23mph 26mph 27mph 25mph
Valley
Valley 23mph 21mph 22mph 25mph 26mph 24mph

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 8 degrees Celsius 10 degrees Celsius 9 degrees Celsius 8 degrees Celsius 7 degrees Celsius 7 degrees Celsius
600m
600m 11 degrees Celsius 12 degrees Celsius 12 degrees Celsius 12 degrees Celsius 10 degrees Celsius 10 degrees Celsius
300m
300m 14 degrees Celsius 16 degrees Celsius 15 degrees Celsius 15 degrees Celsius 14 degrees Celsius 14 degrees Celsius
Valley
Valley 15 degrees Celsius 17 degrees Celsius 17 degrees Celsius 17 degrees Celsius 16 degrees Celsius 15 degrees Celsius
Freezing Level Freezing Level
3400m
3100m
3200m
3000m
2300m
2700m

Additional weather information

Meteorologist's view

There's some uncertainty regarding when on Tuesday the chance of showers is highest, however be aware of what to do if caught in a thunderstorm, despite the risk being low.

Weather

Cloudier during Tuesday compared to Monday with a chance of showers. These could be heavy with a risk of thunder but many places will probably stay dry. Feeling humid and in any sunshine very warm.

Chance of cloud-free hill tops

30% west but 70% in the north and east.

Low cloud and visibility

Periods of cloud above 400-700m at times, lowest in the west, mainly associated with showers. Clearing some higher summits in the north at times. Poor or very poor visibility in the cloud with hill fog at times and temporarily poor in the rain/showers/thunderstorms, otherwise mainly good.

Ground conditions

Please see - https://yrwyddfa.live/

Summit specific forecast