Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for east to southeast flow persisting also for relatively unsettled, but lowering for timing detail of worst of conditions.
This evening forecast
Rain at first, above 800m snow, clearing towards midnight. Severe wind chill at height in strong southeast summit winds. Freezing level around 900m.
Mountain weather hazards
Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.
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.
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.
Storm Force Winds
Storm force winds (gusts over 70mph) make walking very strenuous with any mobility virtually impossible over exposed ground. Where these conditions occur there is a high risk of being blown over and even standing may be impossible at times with a risk of being blown off one’s feet. Basic tasks such as using a map, eating, putting on extra clothing or communication become extremely difficult away from any shelter.
Mountain weather forecast
Fair start, then periods of rain from late morning. Gale to storm force southeast summit winds.
| 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) |
10% | 10% | <05% | 20% | 80% | 80% | 90% | 80% |
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
31
|
S
28
|
SE
29
|
SE
42
|
E
47
|
SE
40
|
SE
40
|
SE
38
|
| 600m |
S
23
|
S
19
|
SE
21
|
SE
29
|
E
33
|
SE
29
|
SE
29
|
SE
27
|
| 300m |
S
15
|
S
12
|
SE
13
|
SE
21
|
SE
24
|
SE
20
|
SE
20
|
SE
19
|
| Valley |
S
15
|
S
12
|
SE
14
|
SE
21
|
SE
24
|
SE
20
|
SE
21
|
SE
20
|
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 | 38 | 33 | 35 | 52 | 60 | 52 | 52 | 50 |
| 600m | 29 | 26 | 29 | 40 | 45 | 41 | 40 | 39 |
| 300m | 27 | 22 | 25 | 37 | 42 | 36 | 36 | 35 |
| Valley | 28 | 23 | 26 | 37 | 41 | 36 | 36 | 35 |
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
0°
|
0°
|
-1°
|
-1°
|
0°
|
4°
|
4°
|
3°
|
| 600m |
2°
|
2°
|
2°
|
1°
|
2°
|
6°
|
6°
|
5°
|
| 300m |
4°
|
4°
|
3°
|
3°
|
5°
|
8°
|
8°
|
8°
|
| Valley |
5°
|
5°
|
4°
|
4°
|
6°
|
9°
|
9°
|
9°
|
| Freezing Level |
800m
|
900m
|
700m
|
700m
|
1,600m
|
1,600m
|
1,600m
|
1,600m
|
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
-8°
|
-8°
|
-9°
|
-11°
|
-9°
|
-4°
|
-4°
|
-4°
|
| 600m |
-5°
|
-4°
|
-5°
|
-7°
|
-5°
|
0°
|
0°
|
0°
|
| 300m |
0°
|
0°
|
-2°
|
-2°
|
-1°
|
4°
|
4°
|
4°
|
| Valley |
1°
|
1°
|
0°
|
-1°
|
1°
|
5°
|
5°
|
5°
|
Additional weather information
Meteorologist's view
Severe wind chill effect receding as the freezing level lifts later in the day. Some risk of gusts reaching storm force (70mph) for a time early afternoon across highest and most exposed ridges and summits.
Weather
Patchy rain and above 700-800m snow, at first overnight, clearing before dawn as the cloud becomes more broken. Cloud soon thickening from the south, bringing patchy rain by late morning, occasionally wintry across highest peaks at first. Outbreaks turning more persistent and heavy for the afternoon, before weakening mid to late evening.
Chance of cloud-free hill tops
40% becoming 10-20% from late morning
Low cloud and visibility
Good or very good, becoming moderate or poor in rain, very poor in snow and within cloud with bases becoming quite extensive from 600m from late morning with patches lower down for the afternoon.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Cloudy with occasional rain, which turns heavier at times for the afternoon and evening, also turning to snow above 800m from late afternoon. Strong southeast summit winds bringing a severe wind chill to higher peaks.
Chance of cloud-free hill tops
20%
Maximum wind speed expected
Southeast mean 30-35mph with gusts reaching 45mph across exposed ridges and summits.
Temperature
- At 800m Plus 4 Celsius decreasing plus 2 Celsius by early evening
- Valley Plus 7 Celsius increasing 10 Celsius for the afternoon
- Freezing level Above summits lowering 900-1000m for the evening
Low cloud and visibility
Good or very good, becoming moderate or poor in rain, very poor in snow and within cloud with bases quite extensive from 600m with patches lower down.
Mountain weather information
Fri 23 Jan
Sunrise:
Sunset:
Mainly cloudy with occasional rain, with snow above 800m. Strong to gale southeast summit winds bringing a severe wind chill at height. Freezing level around 900m.
Sat 24 Jan
Sunrise:
Sunset:
Mainly cloudy with some patchy light rain and summit snow. Strong easterly winds. Freezing level around 800m.
Sun 25 Jan
Sunrise:
Sunset:
Mainly cloudy with patchy light rain and summit snow. Fresh easterly winds. Freezing level around 700-800m.
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.