Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for high pressure holding across the area. Lowering for inversion height and cloud detail.
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
Gale to storm force summit winds. Mainly dry, with brighter spells, these best during the morning.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
00% | 00% | <05% | 10% | 20% | 10% |
Wind direction and speed (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
E
38
|
E
39
|
E
36
|
E
39
|
E
38
|
E
43
|
| 600m |
E
30
|
E
27
|
E
26
|
E
24
|
E
26
|
E
30
|
| 300m |
E
20
|
E
20
|
E
20
|
E
12
|
E
19
|
E
22
|
| Valley |
E
20
|
E
20
|
E
19
|
E
11
|
E
18
|
E
21
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 47 | 48 | 44 | 47 | 47 | 52 |
| 600m | 44 | 41 | 36 | 32 | 36 | 42 |
| 300m | 38 | 38 | 35 | 23 | 33 | 38 |
| Valley | 38 | 37 | 33 | 21 | 32 | 35 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
1°
|
0°
|
0°
|
0°
|
0°
|
0°
|
| 600m |
6°
|
4°
|
3°
|
2°
|
2°
|
2°
|
| 300m |
5°
|
4°
|
5°
|
4°
|
4°
|
4°
|
| Valley |
5°
|
4°
|
6°
|
5°
|
5°
|
6°
|
| Freezing Level |
600m
|
700m
|
800m
|
1,000m
|
1,100m
|
1,600m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-7°
|
-8°
|
-8°
|
-9°
|
-9°
|
-9°
|
| 600m |
0°
|
-3°
|
-3°
|
-5°
|
-5°
|
-5°
|
| 300m |
0°
|
-1°
|
0°
|
0°
|
-1°
|
-1°
|
| Valley |
0°
|
-1°
|
1°
|
2°
|
0°
|
1°
|
Additional weather information
Meteorologist's view
Gusts reaching 60-70mph at times across most exposed ridges and summits, bringing hazardous conditions. Freezing level figures above will be over simplistic at times as the inversion oscillates between 500m and 1000m.
Weather
Dry with sunny spells during the morning. Cloud erratically feeding from the east during the afternoon to bring the chance of some patchy rain from late afternoon, but highest peaks mostly cloud free being above the inversion.
Chance of cloud-free hill tops
75% at first, becoming 25% from late afternoon.
Low cloud and visibility
Good or very good becoming moderate in rain, very low within cloud with bases becoming quite extensive between 600m and 900m from late afternoon, chiefly across the east of the park.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Rather cloudy with some chance of the odd outbreak of light rain or drizzle possible, but most staying dry. Strong easterly summit winds bringing a severe wind chill.
Chance of cloud-free hill tops
30%
Maximum wind speed expected
East 30-35mph with gusts reaching 45mph at times across most exposed ridges and summits.
Temperature
- At 800m Zero to minus 2 Celsius
- Valley Plus 3 Celsius increasing 7 Celsius for the afternoon
- Freezing level 600-800m
Low cloud and visibility
Good or very good becoming moderate in any rain or drizzle, very low within cloud with bases quite extensive at 800m.
Mountain weather information
Mon 29 Dec
Sunrise:
Sunset:
Generally dry with the best of the brighter spells appearing during the morning. Strong summit winds. Freezing level 500-700m.
Tue 30 Dec
Sunrise:
Sunset:
Generally dry with brighter spells building. Light summit winds. Freezing level 500-700m.
Wed 31 Dec
Sunrise:
Sunset:
Rather cloudy but mainly dry. Summit winds now turned west to northwest and strengthening. Freezing level 500-700m.
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.