Mountain weather

Eryri / Snowdonia

Eryri / Snowdonia Mountain weather forecast table

Confidence

Quite high for fair weather on Tuesday and occasionally unsettled otherwise, but lowering for timing detail of worst of later conditions.

Sunrise:
Sunset:

This evening forecast

Fair start, then cloud and rain, initially sleety across highest peaks, reaching from the west from mid-evening, as southerly winds freshen. Freezing level lifting above the summits.

Sunrise:
Sunset:
Mountain hazards

Mountain weather hazards

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

hazard Gales
Gale force winds (gusts over 50mph) make walking difficult and strenuous with a potential to be blown over by gusts. There is often a marked increase in winds through cols or on exposed ridges and summits. Distances can take longer to cover and compass bearings become harder to follow accurately.
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 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.

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

Unsettled with showers and longer periods of rain, summit snow. Gale to severe gale summit winds developing.

Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
Light rain Heavy rain Sleet Light snow shower (day) Heavy snow shower (day) Light snow shower (day) Sleet Sleet
Chance of precipitation
(at 800m)
80% 80% 80% 60% 60% 50% 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 S
22
S
34
W
37
W
34
W
36
W
39
W
40
NW
27
600m S
16
S
24
W
24
W
24
W
26
W
28
W
28
W
19
300m S
10
S
15
W
16
W
15
W
17
W
18
W
19
W
12
Valley S
10
S
15
W
16
W
15
W
18
W
19
W
20
NW
13
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 27 41 46 43 47 51 53 37
600m 21 31 34 33 36 39 40 28
300m 18 27 30 28 31 34 36 23
Valley 18 27 30 28 31 34 36 23

Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m
600m
300m
Valley
Freezing Level
1,400m
1,600m
1,200m
900m
900m
1,000m
1,000m
1,000m

Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m
-3°
-4°
-6°
-8°
-8°
-8°
-8°
-7°
600m
-1°
-4°
-4°
-4°
-4°
-3°
300m
Valley

Additional weather information

Meteorologist's view

Difficult conditions with extensive hill fog, occasionally heavy rain and summit snow coupled with gale to severe gale summit winds which brings a severe wind chill at height.

Weather

Showers and longer periods of rain, snow level lowering to 800-900m mid-morning. Outbreaks turning heavy at times, with some risk of thunder and hail, particularly either side on noon and across western areas of the park. Some limited brighter spells.

Chance of cloud-free hill tops

30%

Low cloud and visibility

Good becoming moderate or poor in rain and sleet, very poor in snow and within cloud with bases quite extensive from 700m.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

Rather cloudy start with showers, snow level 700-800m. Outbreaks frequent through the morning, dwindling gradually from mid-day with bright then clear spells increasing. Fresh to strong northerly summit winds bringing a severe wind chill at height.

Chance of cloud-free hill tops

30% becoming 70% by late afternoon

Maximum wind speed expected

North 30-35mph with gusts reaching 45mph across more exposed ridges and summits.

Temperature

  • At 800m Plus 1-2 Celsius
  • Valley Plus 3 Celsius increasing 10 Celsius for the afternoon
  • Freezing level Around 900m

Low cloud and visibility

Good becoming moderate or poor in showers, very poor within cloud with bases quite extensive from 700m at first, before turning more broken later in the day.

Mountain weather information

Tue 25 Nov

Sunrise:
Sunset:

Dry with bright spells increasing through the day. Northerly summit winds initially fresh. Freezing level around 800m.

Wed 26 Nov

Sunrise:
Sunset:

Dry start with some early brighter spells. Band of rain reaching from the west during the afternoon. Fresh to strong southerly winds. Freezing level soon lifting above summits.

Thu 27 Nov

Sunrise:
Sunset:

Occasional rain, heavy at times. Strong to gale southwest winds. Freezing level above summits.

Updated at:

Summit specific forecast

Mountain summit forecast map

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