Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
Generally high confidence for a mostly unsettled period. Low confidence for details Saturday and extent of any showers on Sunday.
This evening forecast
A dry cloudy start to the evening, but rain spreads east through the evening, briefly falling as snow above 900m. Rain heaviest in the south. Strong southwest winds across the summits, gusting 35-40 mph, with cloud lowering onto the tops as rain sets in. Freezing level 1000m, soon rising above the summits.
Mountain weather hazards
Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.
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.
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.
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.
Mountain weather forecast
Outbreaks of rain and summit snow, snow to lower levels later in the day.
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
|
|
Chance of precipitation (at 800m) |
70% | 70% | 70% | 80% | 80% | 80% | 60% | 30% |
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 |
SW
16
|
E
10
|
E
15
|
NW
17
|
NW
20
|
NW
21
|
N
30
|
NW
27
|
| 600m |
S
13
|
SE
7
|
E
9
|
NW
12
|
NW
14
|
NW
14
|
N
20
|
NW
20
|
| 300m |
S
8
|
E
4
|
NE
5
|
NW
8
|
NW
9
|
NW
9
|
NW
14
|
NW
14
|
| Valley |
S
8
|
E
4
|
NE
5
|
NW
8
|
NW
10
|
NW
10
|
N
15
|
NW
15
|
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 | 21 | 13 | 19 | 21 | 26 | 27 | 39 | 35 |
| 600m | 17 | 10 | 13 | 15 | 20 | 20 | 29 | 28 |
| 300m | 15 | 8 | 10 | 13 | 16 | 16 | 26 | 25 |
| Valley | 15 | 8 | 11 | 14 | 16 | 17 | 27 | 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°
|
0°
|
0°
|
0°
|
0°
|
-1°
|
-1°
|
| 600m |
3°
|
3°
|
2°
|
2°
|
2°
|
2°
|
1°
|
0°
|
| 300m |
5°
|
5°
|
4°
|
4°
|
4°
|
4°
|
3°
|
2°
|
| Valley |
6°
|
6°
|
5°
|
5°
|
5°
|
5°
|
5°
|
4°
|
| Freezing Level |
1,100m
|
1,100m
|
1,000m
|
900m
|
700m
|
800m
|
700m
|
600m
|
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
-5°
|
-3°
|
-6°
|
-6°
|
-7°
|
-7°
|
-9°
|
-9°
|
| 600m |
-1°
|
0°
|
-2°
|
-3°
|
-3°
|
-3°
|
-5°
|
-6°
|
| 300m |
2°
|
4°
|
2°
|
1°
|
0°
|
1°
|
-1°
|
-2°
|
| Valley |
4°
|
5°
|
3°
|
2°
|
2°
|
2°
|
0°
|
-1°
|
Additional weather information
Meteorologist's view
Bitterly cold in the wind. Note some uncertainty in track and depth of low pressure across the UK, with a 30% chance of a deeper low tracking further north, which would likely result in heavier snow to 400m and stronger winds.
Weather
Patchy rain, soon turning to snow above 900m, through the early hours. This likely to turn more persistent through the morning with rain, turning to snow down to 700m, continuing through the afternoon. Turning drier late evening, although still mostly cloudy with scattered showers, falling as snow above 600m.
Chance of cloud-free hill tops
10% or less.
Low cloud and visibility
Very poor visibility for much of the day in rain, snow and low cloud, with cloud bases generally around 500m, lowering during heavier outbreaks. Cloud lifting to 900m, occasionally above the summits in the evening.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Largely dry with some clear spells through the early hours. Then a bright day with some sunny spells and a few showers, falling as snow above 500-600m. Cloud increases towards evening with severe gales across the summits and rain spreading east after dark, briefly preceded by snow on the higher summits.
Chance of cloud-free hill tops
90% during the day, falling to nil late evening.
Maximum wind speed expected
Northwest 20 gusting 30 mph, soon easing to 15-20 mph. Becoming southwest in the afternoon, strengthening to 50 gusting 65 mph in the evening.
Temperature
- At 800m Plus 1 Celsius increasing to 5 Celsius late evening.
- Valley Zero Celsius rising to plus 4 Celsius.
- Freezing level 600m, rising to 800m in the afternoon, above the summits late evening.
Low cloud and visibility
Very good or excellent visibility through the day, some brief patches of cloud possible on the highest summits, but hills largely cloud free. Visibility very poor in the evening in rain and cloud to lower slopes.
Mountain weather information
Mon 1 Dec
Sunrise:
Sunset:
A wet and windy day with strong southwest winds giving a risk of summit gales and occasionally heavy rain. Likely to turn drier with lighter winds by evening. Freezing level above the summits.
Tue 2 Dec
Sunrise:
Sunset:
A largely bright day with sunny spells and a few showers, wintry on the highest summits, with fresh southwest summit winds. Freezing level just above the summits.
Wed 3 Dec
Sunrise:
Sunset:
Most likely cloudier with a few showers on moderate southerly winds. Showers may turn heavier and more frequent later in the day. Freezing level just above the summits.
Updated at:
Summit specific forecast
Mountain summit forecast map
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Key
Mountain summits
Other points of interest
Cluster of multiple stations
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.