Mountain weather

Eryri / Snowdonia

Eryri / Snowdonia Mountain weather forecast table

Confidence

High for dry conditions with light winds on Saturday but lower confidence for cloud detail. Some uncertainty in rain and cloud detail on Sunday and Monday then high confidence for it turning more unsettled and windier from mid-week.

Sunrise:
Sunset:
Mountain hazards

Mountain weather hazards

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

hazard 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.
hazard 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.
hazard 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

Dry and sunny with light winds, then turning cloudier. Cold at height.

Time 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
Sunny day Sunny day Sunny day Cloudy Cloudy Cloudy
Chance of precipitation
(at 800m)
00% 00% 00% 10% 10% 10%

Wind direction and speed (mph)
Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m S
7
S
9
S
10
S
10
S
13
SE
13
600m S
8
S
8
S
10
S
10
S
8
S
8
300m S
4
SE
4
S
7
S
7
SE
3
SE
3
Valley S
4
SE
4
S
7
S
7
S
3
SE
3
Wind gust (mph)
Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m 8 11 13 14 16 16
600m 12 12 13 14 10 10
300m 8 9 11 11 6 6
Valley 8 9 10 10 6 5

Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m
600m
300m
Valley
Freezing Level
600m
600m
800m
900m
1,100m
1,100m

Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m
-3°
-4°
-4°
-2°
-3°
-3°
600m
-2°
-2°
300m
Valley

Additional weather information

Meteorologist's view

A dry and settled day across the National Park with light winds. Feeling cold at height throughout so the full winter clothing will be required.

Weather

Early valley fog patches will gradually lift and clear. Then dry and largely sunny with light winds, before cloud arrives from the east this afternoon. The far west of Snowdonia may remain clear. This evening cloud gradually lowers with hill fog developing.

Chance of cloud-free hill tops

90%, becoming 40% this evening.

Low cloud and visibility

Patchy fog in the valleys at first, otherwise visibility mainly excellent. A little cloud may affect the summits at times this afternoon, lowering to 500 or 600m and becoming more persistent in the evening, especially across eastern areas.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

Cloudy with outbreaks of rain arriving overnight and persisting through the morning, these mostly light in nature but the odd brief heavy burst is possible. Best chance of any bright intervals will be in the afternoon and in the north. Freezing level rising well above all summits with milder air arriving from the south.

Chance of cloud-free hill tops

20%, best chance in north in afternoon.

Maximum wind speed expected

South 15 to 20mph gusts 25mph.

Temperature

  • At 800m Plus 3C rising to 8C.
  • Valley Plus 7C rising to 11 to 13C, locally 14C in north.
  • Freezing level Above summits.

Low cloud and visibility

Extensive cloud and fog above 500 or 600m, perhaps lower at first. Cloud rising above summits at times in the afternoon, mainly in the north. Away from low cloud, visibility rather misty at first but becoming mainly good with distant hills visible by afternoon with just brief reductions in rain.

Mountain weather information

Mon 9 Mar

Sunrise:
Sunset:

Mostly cloudy with outbreaks of rain, these rather light and sporadic. Mainly light southwest winds, fresh on the tops. Mild conditions with freezing level well above summits.

Tue 10 Mar

Sunrise:
Sunset:

Dry with bright spells then rain, heavy at times, arriving from the west through the evening. Southerly winds becoming strong with severe gales developing on the tops. Freezing level above summits.

Wed 11 Mar

Sunrise:
Sunset:

Heavy rain quickly clearing then broken cloud and scattered showers. Severe gales over the summits gradually easing. Freezing level above summits.

Updated at:

Summit specific forecast

Mountain summit forecast map

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