Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for dry and bright weather on New Year's Eve but lower confidence in cloud amounts later in the day. High for very cold conditions with snow showers to start the New Year but lower for day-to-day extent of showers.
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.
Mountain weather forecast
Dry with sunny spells at first but cloud increasing. Cold.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
00% | 00% | 00% | 00% | <05% | <05% |
Wind direction and speed (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
NW
12
|
NW
13
|
W
13
|
W
15
|
W
22
|
W
26
|
| 600m |
N
3
|
NW
4
|
W
7
|
W
9
|
W
11
|
W
15
|
| 300m |
S
2
|
W
2
|
W
3
|
W
6
|
W
6
|
W
10
|
| Valley |
S
2
|
W
2
|
W
4
|
W
7
|
W
7
|
W
10
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 15 | 17 | 15 | 18 | 26 | 33 |
| 600m | 5 | 7 | 10 | 12 | 15 | 21 |
| 300m | 3 | 5 | 6 | 11 | 14 | 19 |
| Valley | 3 | 6 | 7 | 12 | 15 | 20 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-2°
|
-2°
|
-2°
|
-2°
|
-2°
|
-3°
|
| 600m |
0°
|
0°
|
0°
|
0°
|
0°
|
0°
|
| 300m |
2°
|
2°
|
3°
|
3°
|
3°
|
3°
|
| Valley |
3°
|
3°
|
4°
|
5°
|
4°
|
4°
|
| Freezing Level |
400m
|
400m
|
500m
|
600m
|
600m
|
500m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-8°
|
-8°
|
-8°
|
-8°
|
-10°
|
-11°
|
| 600m |
-2°
|
-3°
|
-3°
|
-4°
|
-4°
|
-6°
|
| 300m |
0°
|
0°
|
1°
|
0°
|
0°
|
-1°
|
| Valley |
1°
|
2°
|
3°
|
2°
|
1°
|
0°
|
Additional weather information
Meteorologist's view
A bright start but feeling cold with a severe wind chill developing on the tops as the winds pick up. Full winter clothing will be required. Note the deterioration in navigation conditions later in the day.
Weather
Clear spells at first with widespread frost and patchy freezing fog, which may last through the morning in places. Otherwise, a dry day with sunny spells but cloud amounts increasing from the north as the day goes on.
Chance of cloud-free hill tops
90%, gradually becoming 60%. Best chance in the south.
Low cloud and visibility
Mainly excellent visibility at first but some patchy freezing fog in the valleys. Areas of cloud above 500-600m moving in from the north, mainly in the afternoon, bringing very poor visibility at times.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Mainly dry overnight but then outbreaks of rain will move south before dawn, wintry on higher tops. This clearing away by lunchtime, then there will be a mixture of sunny spells and a few showers, falling as sleet or snow above 400m and giving a light covering of snow in places. A severe wind chill.
Chance of cloud-free hill tops
60% becoming 20% before dawn, then becoming 70% for the afternoon.
Maximum wind speed expected
West or Northwest 25 to 35mph gusts 45-55mph.
Temperature
- At 800m 0C to Minus 2C.
- Valley Plus 4 or 5C.
- Freezing level 400m, rising to 800m early morning, then falling to 500m.
Low cloud and visibility
Extensive cloud above 400-600m early in the morning then becoming patchier for the afternoon. Generally good visibility away from cloud but falling to a few km or less at times in showers.
Mountain weather information
Fri 2 Jan
Sunrise:
Sunset:
Occasional snow at first, clearing to sunny spells and snow showers. A severe wind chill with strong northwest winds. Freezing level falling to valley level.
Sat 3 Jan
Sunrise:
Sunset:
Further bright spells and snow showers and remaining bitterly cold with strong northwest winds. Ground frozen to valley level.
Sun 4 Jan
Sunrise:
Sunset:
Expected to remain very cold with further snow showers but winds and showers may start to ease later. Ground frozen to valley level.
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.