Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for Tuesday, and high for a change to colder weather for the rest of the working week.
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.
Mountain weather forecast
Cloudy with showers, wintry on the higher tops
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
60% | 70% | 80% | 80% | 80% | 80% |
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
21
|
SW
29
|
W
31
|
W
30
|
NW
27
|
NW
24
|
| 600m |
S
14
|
SW
18
|
W
22
|
W
20
|
NW
17
|
NW
13
|
| 300m |
S
7
|
SW
12
|
W
15
|
W
13
|
NW
11
|
NW
8
|
| Valley |
S
7
|
SW
12
|
W
16
|
W
14
|
NW
12
|
NW
8
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 24 | 34 | 39 | 37 | 33 | 30 |
| 600m | 17 | 23 | 29 | 26 | 24 | 18 |
| 300m | 12 | 23 | 26 | 24 | 20 | 16 |
| Valley | 12 | 23 | 26 | 24 | 21 | 17 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
0°
|
0°
|
1°
|
1°
|
1°
|
0°
|
| 600m |
2°
|
3°
|
3°
|
3°
|
3°
|
2°
|
| 300m |
4°
|
5°
|
6°
|
6°
|
5°
|
4°
|
| Valley |
5°
|
6°
|
7°
|
7°
|
6°
|
6°
|
| Freezing Level |
800m
|
1,000m
|
1,000m
|
1,000m
|
1,000m
|
900m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-7°
|
-7°
|
-7°
|
-6°
|
-6°
|
-7°
|
| 600m |
-3°
|
-3°
|
-2°
|
-2°
|
-2°
|
-2°
|
| 300m |
1°
|
1°
|
2°
|
2°
|
1°
|
1°
|
| Valley |
2°
|
3°
|
3°
|
4°
|
3°
|
3°
|
Additional weather information
Meteorologist's view
A significant wind chill likely at height. Appropriate clothing and equipment essential.
Weather
A cloudy day with showers, these occasionally heavy and becoming more frequent in the afternoon and evening. Sleet and snow can be expected above 700-800 metres. More in the way of drier weather to start the day.
Chance of cloud-free hill tops
40%, best chance in the morning.
Low cloud and visibility
Poor in cloud down to 600-700 metres, this patchy in the morning but becoming more widespread through the afternoon and evening as showers become more frequent.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
A cloudy start with some sleet and snow, occasionally heavy. This then dying out by mid-morning. Then the afternoon will be much brighter and largely dry. Dry and clear in the evening. Strong northerly winds leading to a significant wind chill.
Chance of cloud-free hill tops
10% initially, becoming 80% into the afternoon.
Maximum wind speed expected
Northerly 40-45mph.
Temperature
- At 800m Plus 1 falling to minus 1 Celsius
- Valley Plus 2 rising to 4 Celsius
- Freezing level 900 metres in the early hours, falling to 300 metres by late morning
Low cloud and visibility
Poor in widespread low cloud down to 400 to 700 metres at first, this clearing by late morning. Then excellent visibility for the rest of the day with little in the way of summit cloud.
Mountain weather information
Thu 20 Nov
Sunrise:
Sunset:
Dry with sunny intervals. Cold northerly winds.
Fri 21 Nov
Sunrise:
Sunset:
Most of the day will be dry and cold. Rain, preceded by some sleet and snow, will spread east through the evening.
Sat 22 Nov
Sunrise:
Sunset:
Cloudy with rain, some snow on the summits in the early hours. Drier weather with a few showers will spread from the west during the day but low confidence in timing of this.
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.