Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for the changeable conditions this week, lower for day to day details.
This evening forecast
The last of the persistent heavy rain will clear during the evening, with cloud breaking towards mid evening, though a few showers will follow later, turning to snow above 800-900m towards midnight. Strong to gale southwesterly winds also starting to ease down.
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.
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.
Thunderstorms
Lightning is a significant mountain hazard which can result in serious injury or death. Mountain terrain often leaves one highly exposed to lightning strikes. Hail may give unpleasant conditions with torrential rain and localised flash flooding also possible, mainly in Summer months.
Mountain weather forecast
A few bright or sunny intervals but often cloudy, with occasional showers which will be of snow on the highest hills, and with a small chance of lightning.
| 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) |
30% | 50% | 30% | 30% | 20% | 60% | 50% | 40% |
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 |
SW
30
|
SW
34
|
SW
32
|
SW
31
|
SW
27
|
S
24
|
S
23
|
S
21
|
| 600m |
SW
19
|
SW
21
|
SW
20
|
S
20
|
S
19
|
S
17
|
S
16
|
S
17
|
| 300m |
SW
11
|
SW
12
|
SW
12
|
S
12
|
S
13
|
S
12
|
S
11
|
S
11
|
| Valley |
SW
11
|
SW
12
|
SW
11
|
S
12
|
S
13
|
S
12
|
S
11
|
S
12
|
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 | 37 | 41 | 39 | 39 | 34 | 30 | 28 | 27 |
| 600m | 25 | 30 | 28 | 26 | 26 | 23 | 22 | 23 |
| 300m | 21 | 26 | 25 | 24 | 22 | 22 | 20 | 21 |
| Valley | 21 | 26 | 24 | 23 | 22 | 22 | 21 | 22 |
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
1°
|
1°
|
1°
|
1°
|
1°
|
1°
|
1°
|
0°
|
| 600m |
3°
|
3°
|
3°
|
3°
|
3°
|
3°
|
3°
|
2°
|
| 300m |
6°
|
6°
|
5°
|
5°
|
6°
|
5°
|
5°
|
4°
|
| Valley |
7°
|
7°
|
7°
|
7°
|
8°
|
7°
|
6°
|
6°
|
| Freezing Level |
1,000m
|
1,000m
|
1,000m
|
1,000m
|
1,000m
|
1,000m
|
1,000m
|
1,000m
|
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
-6°
|
-7°
|
-7°
|
-6°
|
-6°
|
-6°
|
-6°
|
-6°
|
| 600m |
-2°
|
-2°
|
-2°
|
-2°
|
-2°
|
-2°
|
-3°
|
-3°
|
| 300m |
2°
|
2°
|
2°
|
1°
|
2°
|
1°
|
1°
|
1°
|
| Valley |
4°
|
3°
|
4°
|
3°
|
4°
|
3°
|
3°
|
2°
|
Additional weather information
Meteorologist's view
Poor underfoot conditions due to the recent very wet weather with some fast flowing, swollen watercourses especially at first, and some flooding in car parks and access roads.
Weather
Bright or sunny intervals but often cloudy, with occasional showers. These will be quite heavy at times, with the chance of thunder, and falling as snow above 800-900m.
Chance of cloud-free hill tops
30%.
Low cloud and visibility
Broken, occasionally overcast cloud at 600-700m with some patches to 450m. Visibility occasionally good away from cloud and showers, but falling moderate to poor in the showers, and very poor in hill fog above the cloud line and in snow.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Clear or sunny intervals and occasional showers, wintry on summits in the morning. More persistent rain arriving later in the evening.
Chance of cloud-free hill tops
40%
Maximum wind speed expected
Southwesterly 25 gusts 35mph increasing 40 gusts 55mph towards evening.
Temperature
- At 800m Plus 1 rising to Plus 3 Celsius
- Valley Plus 5 rising to Plus 9 Celsius
- Freezing level 900m rising above summits before morning
Low cloud and visibility
Broken to overcast cloud bases 500-700m with the odd lower patch. Visibility below the cloud, often good but moderate briefly poor as showers pass through.
Mountain weather information
Thu 4 Dec
Sunrise:
Sunset:
Mainly cloudy with showers, falling as snow above 600-700m. Moderate southwesterly winds.
Fri 5 Dec
Sunrise:
Sunset:
A dry morning with sunny spells and patchy valley fog. Becoming cloudier in afternoon then rain and strong winds in the evening. Low confidence.
Sat 6 Dec
Sunrise:
Sunset:
Confidence remains low, but most likely a showery day with strong to gale force westerly 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.