Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for wet and windy conditions arriving on New Year's Eve then low confidence for the timings of heavy rain or snow clearing south during New Year's Day and transition to colder conditions.
This evening forecast
Cloudy with the odd spot of rain Strengthening southwesterly winds with gales later on the tops. Freezing level above summits.
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.
Heavy Persistent Rain
Heavy and persistent rain can lead to drenched clothing and footwear with waterproofs often becoming soaked through, especially if accompanied by strong winds. This can lead to significant loss of body heat and an increased likelihood of hypothermia. Terrain may turn increasingly boggy underfoot while streams can flood and become impassable. There may also be a risk of flooding in valleys or glens. If there is snow cover, a heightened avalanche hazard is possible and avalanche reports should be consulted where available.
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.
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 start then turning very wet and windy. Storm force winds on the tops.
| 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% | 20% | 30% | 90% | 90% | 90% | 90% |
Wind direction and speed (mph)
Altitude above mean sea level
| 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|---|---|
| 900m |
SW
39
|
SW
41
|
SW
46
|
SW
52
|
SW
55
|
SW
53
|
SW
42
|
SW
37
|
| 600m |
SW
25
|
SW
30
|
SW
34
|
SW
38
|
SW
41
|
SW
40
|
SW
29
|
SW
27
|
| 300m |
SW
17
|
SW
20
|
SW
23
|
SW
26
|
SW
26
|
SW
25
|
SW
20
|
SW
18
|
| Valley |
SW
18
|
SW
20
|
SW
24
|
SW
26
|
SW
28
|
SW
25
|
SW
20
|
SW
18
|
Wind gust (mph)
Altitude above mean sea level
| 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|---|---|
| 900m | 50 | 53 | 60 | 68 | 73 | 71 | 56 | 50 |
| 600m | 35 | 41 | 48 | 53 | 58 | 57 | 43 | 39 |
| 300m | 31 | 36 | 42 | 47 | 49 | 48 | 38 | 34 |
| Valley | 33 | 38 | 43 | 47 | 52 | 47 | 37 | 33 |
Altitude above mean sea level
| 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|---|---|
| 900m |
3°
|
3°
|
3°
|
3°
|
4°
|
5°
|
4°
|
4°
|
| 600m |
5°
|
5°
|
5°
|
6°
|
6°
|
6°
|
6°
|
6°
|
| 300m |
7°
|
8°
|
7°
|
8°
|
8°
|
8°
|
8°
|
8°
|
| Valley |
9°
|
9°
|
9°
|
9°
|
9°
|
10°
|
10°
|
9°
|
| Freezing Level |
1,300m
|
1,300m
|
1,400m
|
1,600m
|
2,200m
|
2,100m
|
1,800m
|
1,600m
|
Altitude above mean sea level
| 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|---|---|
| 900m |
-5°
|
-5°
|
-5°
|
-5°
|
-5°
|
-3°
|
-3°
|
-4°
|
| 600m |
-1°
|
-1°
|
-1°
|
-1°
|
-1°
|
0°
|
0°
|
0°
|
| 300m |
4°
|
3°
|
3°
|
3°
|
3°
|
4°
|
4°
|
4°
|
| Valley |
5°
|
5°
|
5°
|
5°
|
5°
|
6°
|
6°
|
5°
|
Additional weather information
Meteorologist's view
Gusts of 70 to 80mph on high ridges and summits will make walking almost impossible and hazardous. Severe conditions setting in from heavy rain, strong winds and wind chill.
Weather
Mainly dry overnight and much of the morning with patchy light rain. Rain becoming persistent and heavy from late morning onwards with drenching conditions for the rest of the day. Very windy with stormy conditions on the tops.
Chance of cloud-free hill tops
30% becoming 10% in afternoon.
Low cloud and visibility
Extensive cloud above 700 or 800m lowering to 500m during the afternoon. Away from low cloud, mainly good visibility at first but becoming poor once rain sets in.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Persistent and heavy rain and sleet, with snow mainly above 400m but perhaps to lower levels, overnight and in the morning. This is expected to clear south by afternoon but timings and snow levels are uncertain at this stage. Clear spells and showers following, wintry above 500m at first then to lower levels in evening.
Chance of cloud-free hill tops
10%, becoming 70% in afternoon.
Maximum wind speed expected
Southwesterly 40mph gusts 55mph overnight becoming Westerly or Northwesterly 25 to 30mph gusts 40mph.
Temperature
- At 800m Plus 1C falling to Minus 1C, then Minus 4 C in evening.
- Valley Plus 5 or 6C, falling to Plus 2C later.
- Freezing level 900m falling to 400m.
Low cloud and visibility
Extensive cloud above 500m overnight and to start the morning with poor or very poor visibility in rain or snow. Improving in the afternoon, but occasionally poor in wintry showers.
Mountain weather information
Thu 2 Jan
Sunrise:
Sunset:
Mainly dry with sunny spells and scattered snow showers. Strong northerly winds on the tops with severe wind chill. Freezing level down to 200m.
Fri 3 Jan
Sunrise:
Sunset:
Bright spells and wintry showers, turning to rain below 300m. Brisk northwest winds. Freezing level rising to 500m.
Sat 4 Jan
Sunrise:
Sunset:
Bright intervals and scattered wintry showers, but mainly rain on low slopes. Light winds. Freezing level around 400m.
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.