Mountain weather

Eryri / Snowdonia

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Eryri / Snowdonia Mountain weather forecast table

Confidence

High for increasingly unsettled and windy conditions through this period. Lower confidence for cloud and rain details which become more uncertain as we go through the week.

Sunrise:
Sunset:

This evening forecast

Mainly dry but some areas of cloud down to low slopes giving difficult navigation conditions. Some clear spells will develop, mainly across the west of the National Park. Light winds. Freezing level above 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 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 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.
Mountain hazards explained

Mountain weather forecast

Mainly dry with sunny spells. Low cloud and patch rain spreading north in afternoon. Becoming breezy on the tops.

Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
 Partly cloudy (night) Partly cloudy (night) Clear night Sunny intervals Sunny intervals Fog Fog Partly cloudy (night)
Chance of precipitation
(at 800m)
 10% 10% 10% 10% 20% 40% 40% 20%

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 SE
16
 SE
14
 SE
15
 SE
19
 SE
21
 SE
21
 SE
26
 SE
32
600m SE
12
 SE
10
 SE
10
 SE
13
 S
15
 SE
15
 SE
18
 SE
22
300m SE
7
 SE
6
 SE
6
 SE
6
 S
7
 SE
9
 SE
10
 SE
14
Valley SE
7
 SE
6
 SE
6
 SE
7
 S
8
 SE
9
 SE
11
 SE
14
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 18 16 17 22 24 25 31 39
600m 15 13 12 16 19 19 23 28
300m 11 9 8 11 14 16 20 25
Valley 11 9 8 11 14 16 20 26

Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m
1°
1°
1°
2°
2°
2°
2°
1°
600m
3°
3°
3°
3°
4°
5°
4°
4°
300m
4°
4°
4°
4°
6°
7°
6°
6°
Valley
5°
5°
5°
5°
7°
8°
7°
7°
Freezing Level
900m
900m
900m
1,000m
1,100m
1,200m
1,200m
1,200m

Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m
-5°
-4°
-4°
-4°
-4°
-4°
-5°
-6°
600m
-1°
-1°
-1°
-1°
0°
0°
-1°
-2°
300m
2°
2°
2°
2°
4°
4°
3°
2°
Valley
2°
3°
3°
2°
5°
6°
4°
3°

Additional weather information

Meteorologist's view

Valley temperatures may be below freezing places in the morning. A chance of sunshine with good views of a cloud inversion in the morning but note the more extensive low cloud spreading north during the afternoon giving some difficult navigation conditions.

Weather

Clear spells overnight with patchy fog and frost in the valley, this slow to clear. Dry with sunny spells in the morning into early afternoon. Cloud and patchy light rain will spread north during the afternoon but the far north of the Park may remain bright until dusk. Patchy rain will clear away northeast during the evening.

Chance of cloud-free hill tops

80% in morning becoming 30% in afternoon.

Low cloud and visibility

Patchy low cloud on low slopes in the morning but higher slopes remaining clear above the inversion. Cloud becoming rather extensive from the south during the afternoon with bases 300 to 500m, then lifting to the summits in the evening. Away from low cloud, mainly good visibility but a few kilometres at times in rain later.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

Largely dry with a few bright or clear intervals. The main feature will be the strengthening southerly winds with severe gales or storm force winds on the tops in the afternoon and evening making walking difficult and potentially dangerous. Outbreaks of rain spread east during the evening.

Chance of cloud-free hill tops

60%.

Maximum wind speed expected

South or Southeast 20 gusts 30mph increasing to 40-50mph gusts 60-70mph in afternoon.

Temperature

  • At 800m Plus 1 or 2C.
  • Valley Plus 6 to 8C.
  • Freezing level Just above summits.

Low cloud and visibility

Occasional cloud cover above 600m with mainly good visibility away from cloud.

Mountain weather information

Wed 21 Jan

Sunrise:
Sunset:

Rather cloudy with occasional rain and summit snow but there could be a period of drier and brighter weather during the day. Very windy with severe gale force southerly winds on the tops. Freezing level down to 900m.

Thu 22 Jan

Sunrise:
Sunset:

Mainly cloudy with showers or longer spells of rain and summit sleet. Gale force southerly winds gradually easing. Freezing level above summits.

Fri 23 Jan

Sunrise:
Sunset:

Remaining unsettled with showers or longer spells of rain and summit sleet. Fresh southerly winds on the tops. Freezing level above summits.

Updated at:
Mountain weather explained

Summit specific forecast

Mountain summit forecast map

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The Eryri (Snowdonia) mountains are made up of 90 mountain peaks including the tallest mountain in Wales, Yr Wyddfa (Snowdon), standing at 1,085 metres.

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