Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for unsettled, but lowering for the confidence in the timing detail of worst of the weather.
Mountain weather hazards
Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.
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.
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.
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.
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.
Mountain weather forecast
Overcast with rain and summit snow at first. Improving to scattered showers and brighter spells mid-morning. Winds initially strong to gale. Freezing level lowering later.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
60% | 80% | 60% | 40% | 20% | 20% |
Wind direction and speed (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
SE
41
|
SW
21
|
W
26
|
W
24
|
W
20
|
SW
21
|
| 600m |
SE
29
|
W
17
|
W
17
|
W
14
|
SW
11
|
SW
13
|
| 300m |
SE
22
|
W
11
|
W
12
|
W
9
|
W
6
|
SW
8
|
| Valley |
SE
22
|
W
12
|
W
12
|
W
10
|
W
7
|
SW
9
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 48 | 26 | 32 | 29 | 25 | 27 |
| 600m | 36 | 22 | 22 | 20 | 16 | 18 |
| 300m | 35 | 20 | 20 | 18 | 14 | 17 |
| Valley | 35 | 20 | 21 | 19 | 15 | 18 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
2°
|
1°
|
0°
|
-1°
|
0°
|
-1°
|
| 600m |
4°
|
2°
|
2°
|
2°
|
2°
|
2°
|
| 300m |
6°
|
4°
|
4°
|
4°
|
4°
|
4°
|
| Valley |
8°
|
5°
|
6°
|
6°
|
5°
|
5°
|
| Freezing Level |
1,300m
|
900m
|
800m
|
800m
|
800m
|
700m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-6°
|
-6°
|
-8°
|
-8°
|
-7°
|
-7°
|
| 600m |
-3°
|
-3°
|
-4°
|
-3°
|
-2°
|
-3°
|
| 300m |
1°
|
0°
|
0°
|
1°
|
1°
|
0°
|
| Valley |
3°
|
1°
|
2°
|
3°
|
3°
|
2°
|
Additional weather information
Meteorologist's view
Very difficult conditions in the extensive early morning hill fog, heavy rain and later summit snow, coupled with a severe wind chill at height. Low risk of early summit gales.
Weather
A cloudy start to the morning with occasional rain and summit snow. Snow level 1000m lowering 700m by mid-morning as the rain and summit snow becomes heavy and persistent, then gradually clears northeastwards early afternoon. Cloudy conditions will linger with a chance of patchy light rain and summit snow until late afternoon. Then broken cloud and clear spells develop, while isolated showers may arrive, these wintry above 700m.
Chance of cloud-free hill tops
10% increasing 70% by late afternoon
Low cloud and visibility
Good becoming moderate or poor in rain, very poor in snow and within cloud with bases extensive at 600m at first, before lifting and breaking early afternoon.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Bright spells and isolated showers through the morning, then an area of often heavy rain spread northeastwards from noon. Outbreaks wintry across higher summits. Severe gales to storm force summit winds developing for a time in the afternoon. Severe wind chill.
Chance of cloud-free hill tops
40% for the morning becoming less than 10% for the afternoon.
Maximum wind speed expected
Southeast increasing 60-70mph with gusts reaching 80-85mph across most exposed ridges and summits.
Temperature
- At 800m Zero to Plus 1 Celsius
- Valley Plus 1 Celsius increasing to 9 Celsius for the afternoon
- Freezing level 800-900m
Low cloud and visibility
Good becoming moderate or poor in rain, very poor in snow and within cloud with bases becoming extensive at 600m for the afternoon.
Mountain weather information
Sat 6 Dec
Sunrise:
Sunset:
A showery day with outbreaks frequent and heavy at times bringing the risk of hail and thunder. Fresh to strong summit winds. Freezing level close to the highest summits.
Sun 7 Dec
Sunrise:
Sunset:
Cloudy with occasionally heavy rain, clearing drier and brighter conditions through the afternoon. Winds veering to the southwest and strengthening. Freezing level close to the highest summits.
Mon 8 Dec
Sunrise:
Sunset:
Mainly dry with bright or sunny spells, until gales or storm force winds and heavy rain probably arrive through the evening. Freezing level above 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.