Mountain weather

Eryri / Snowdonia

Yellow warning

Yellow weather warnings in force for Eryri / Snowdonia

Eryri / Snowdonia Mountain weather forecast table

Confidence

High for cold weather to remain across Snowdonia for most of the period. The main uncertainty is for details of Atlantic weather systems from Tuesday which may bring periods of snow, then slightly milder conditions.

Sunrise:
Sunset:

This evening forecast

Clear spells and occasional snow showers with temperatures remaining below freezing. Strong northerly winds and a very severe wind chill on the tops.

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 Blizzards
Blizzards and whiteouts present challenging and serious conditions due to a combination of falling or blowing snow, strong winds and cold temperatures. They can be highly disorientating, often resulting in near-zero visibility with limited or no visual references and no distinction between ground and sky. Cliff edges and cornices may not be apparent, even close up. These conditions require very good navigational skills.
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 Heavy Persistent Snow
Heavy snow can lead to rapid changes in underfoot conditions and paths may become treacherous or hidden. It also brings very poor visibility and often makes navigation much more challenging. When deep snow accumulates progress is often time consuming and strenuous, significantly affecting the distance one can travel on foot. Deep drifts can develop if snow is combined with strong winds. A heightened avalanche risk is possible and avalanche reports should be consulted where available.
hazard 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.

Mountain weather forecast

Snow showers. Very cold with severe wind chill.

Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
Light snow shower (night) Light snow shower (night) Light snow shower (night) Light snow shower (day) Heavy snow shower (day) Heavy snow shower (day) Heavy snow shower (night) Heavy snow shower (night)
Chance of precipitation
(at 800m)
40% 40% 40% 40% 60% 70% 70% 70%

Wind direction and speed (mph)
Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m NW
30
NW
28
NW
26
NW
22
NW
22
NW
25
NW
27
NW
24
600m NW
15
NW
16
NW
13
NW
11
W
12
NW
16
NW
18
NW
15
300m NW
8
NW
9
NW
6
NW
6
W
5
NW
9
NW
11
NW
9
Valley NW
9
NW
10
NW
7
NW
7
W
6
NW
10
NW
12
NW
10
Wind gust (mph)
Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m 36 34 32 27 27 31 34 30
600m 21 22 18 15 17 22 25 21
300m 20 18 15 13 12 18 21 18
Valley 21 19 16 15 13 19 22 19

Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m
-5°
-5°
-5°
-5°
-4°
-4°
-4°
-4°
600m
-2°
-3°
-3°
-3°
-2°
-2°
-2°
-2°
300m
-1°
-1°
-2°
-2°
-1°
Valley
Freezing Level
0m
0m
0m
100m
200m
200m
300m
200m

Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m
-14°
-14°
-14°
-14°
-12°
-13°
-13°
-13°
600m
-9°
-10°
-9°
-9°
-8°
-8°
-9°
-8°
300m
-5°
-6°
-5°
-5°
-3°
-4°
-5°
-5°
Valley
-3°
-4°
-4°
-4°
-2°
-2°
-4°
-4°

Additional weather information

Meteorologist's view

A bitterly cold day at all heights with serious winter conditions on higher slopes and ridges.

Weather

Clear spells and occasional snow showers overnight. A few bright intervals, otherwise largely cloudy with snow showers becoming more widespread during the day. Blizzard conditions on the tops at times in heavier showers with a small chance of thunder.

Chance of cloud-free hill tops

20%, best chance in south.

Low cloud and visibility

Visibility often poor as snow showers move through, down to less than a kilometre at times with also some patchy fog above 500m. Temporary blizzard conditions in heavier showers with blowing snow. Best of any breaks across the south of the Park.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

Clear or bright spells and occasional snow showers, mainly across the west. Remaining very cold with a severe wind chill on the tops in the northerly winds.

Chance of cloud-free hill tops

60%.

Maximum wind speed expected

North 20mph gusts 30mph.

Temperature

  • At 800m Minus 5C.
  • Valley Minus 2C rising to Plus 2C during day. Shaded slopes staying below freezing.
  • Freezing level Ground frozen at all heights.

Low cloud and visibility

Excellent visibility between showers then suddenly poor or very poor at times with patchy fog above 500m.

Mountain weather information

Tue 6 Jan

Sunrise:
Sunset:

A bright start then outbreaks of snow spreading eastwards, possibly turning heavy and persistent later. The snow may also turn to rain or sleet on lower slopes later. Fresh or strong westerly winds. Freezing level rising to 600m later.

Wed 7 Jan

Sunrise:
Sunset:

Outbreaks of rain, sleet and snow clearing east overnight then dry and bright again. Remaining cold with strong northerly winds on the tops. Freezing level lowering to 400m.

Thu 8 Jan

Sunrise:
Sunset:

Spells of sleet or snow, turning to rain on lower slopes as milder conditions try to push in from the Atlantic. Low confidence.

Updated at:

Summit specific forecast

Mountain summit forecast map

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