Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for the mobile nature of the westerly weather pattern, but lowering for the transitional timing detail.
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.
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.
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 weather forecast
Cloudy with patchy rain by day. Summit gales developing from late morning.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
60% | 30% | 40% | 80% | 70% | >95% |
Wind direction and speed (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
SW
36
|
SW
40
|
S
39
|
S
48
|
S
51
|
S
47
|
| 600m |
SW
23
|
S
27
|
S
29
|
S
33
|
S
33
|
S
32
|
| 300m |
S
13
|
S
18
|
S
19
|
S
22
|
S
21
|
S
20
|
| Valley |
S
13
|
S
18
|
S
19
|
S
21
|
S
21
|
S
21
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 41 | 47 | 48 | 58 | 61 | 58 |
| 600m | 28 | 33 | 38 | 43 | 43 | 42 |
| 300m | 25 | 31 | 34 | 38 | 38 | 37 |
| Valley | 25 | 31 | 34 | 38 | 38 | 38 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
1°
|
1°
|
2°
|
3°
|
4°
|
4°
|
| 600m |
3°
|
4°
|
5°
|
5°
|
5°
|
6°
|
| 300m |
5°
|
6°
|
7°
|
7°
|
7°
|
8°
|
| Valley |
6°
|
7°
|
8°
|
8°
|
8°
|
9°
|
| Freezing Level |
1,000m
|
1,100m
|
1,300m
|
1,700m
|
1,700m
|
2,100m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-8°
|
-7°
|
-5°
|
-5°
|
-5°
|
-3°
|
| 600m |
-3°
|
-3°
|
-2°
|
-1°
|
-1°
|
0°
|
| 300m |
1°
|
1°
|
2°
|
2°
|
3°
|
4°
|
| Valley |
3°
|
3°
|
4°
|
4°
|
4°
|
5°
|
Additional weather information
Meteorologist's view
Quite extensive hill fog bringing significant navigational challenges. Severe wind chill extending to mid-levels.
Weather
A cloudy day with patchy light rain developing, with occasional snow across highest peaks through to mid-morning. Outbreaks most persistent across the western areas of the park and during the afternoon. A band of rain, locally heavy, will arrive from the west by late-afternoon, moving eastwards during the evening.
Chance of cloud-free hill tops
10-20%
Low cloud and visibility
Good or very good becoming moderate or poor in rain, very poor within cloud, which will be quite extensive from 500m.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Most staying dry with only a few well scattered showers crossing the Park, most of these expected during the afternoon. Strong to gale west to southwest summit winds bringing a severe wind chill at height. Freezing level above summits.
Chance of cloud-free hill tops
75%
Maximum wind speed expected
West to southwest mean 35mph, with gusts reaching 50mph across more exposed ridges and summits.
Temperature
- At 800m Plus 2 Celsius increasing 4 Celsius for the afternoon
- Valley Plus 6 Celsius increasing 11 Celsius for the afternoon
- Freezing level 1000m at dawn lifting above summits during the morning
Low cloud and visibility
Good or very good becoming moderate or poor in showers, very poor within cloud, which will occasionally lower to 600m.
Mountain weather information
Thu 12 Mar
Sunrise:
Sunset:
Rather cloudy with frequent showers or longer periods of rain, and later summit snow, that turns heavy at times. Strong to gale force summit winds.
Fri 13 Mar
Sunrise:
Sunset:
Frequent showers, heavy at times with the risk of thunderstorms, with snow level lowering to around 600m. Strong summit winds bringing severe wind chill at height. Freezing level 700m.
Sat 14 Mar
Sunrise:
Sunset:
Rather cloudy with some patchy light rain. Strong summit winds.
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.