Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for the generally unsettled weather, but lower for the details of the wind and precipitation on Friday.
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.
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.
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
Mainly cloudy with showers, wintry on the tops. Cold and windy at height.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
60% | 60% | 60% | 40% | 20% | 20% |
Wind direction and speed (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
S
28
|
S
32
|
S
29
|
S
28
|
S
32
|
S
37
|
| 600m |
S
21
|
S
22
|
S
21
|
S
20
|
S
22
|
S
26
|
| 300m |
S
13
|
S
15
|
S
15
|
S
13
|
S
14
|
S
17
|
| Valley |
S
14
|
S
15
|
S
15
|
S
13
|
S
15
|
S
18
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 32 | 37 | 34 | 34 | 37 | 44 |
| 600m | 25 | 27 | 27 | 25 | 28 | 33 |
| 300m | 23 | 25 | 24 | 22 | 26 | 30 |
| Valley | 24 | 25 | 24 | 23 | 26 | 31 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
1°
|
1°
|
2°
|
2°
|
2°
|
2°
|
| 600m |
3°
|
3°
|
4°
|
4°
|
4°
|
4°
|
| 300m |
5°
|
5°
|
6°
|
6°
|
6°
|
6°
|
| Valley |
6°
|
6°
|
7°
|
8°
|
7°
|
7°
|
| Freezing Level |
1,000m
|
1,000m
|
1,100m
|
1,200m
|
1,200m
|
1,100m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-7°
|
-7°
|
-6°
|
-5°
|
-6°
|
-7°
|
| 600m |
-3°
|
-3°
|
-2°
|
-1°
|
-2°
|
-2°
|
| 300m |
1°
|
1°
|
2°
|
3°
|
2°
|
2°
|
| Valley |
2°
|
2°
|
3°
|
4°
|
4°
|
3°
|
Additional weather information
Meteorologist's view
It will feel much colder on the tops compared to down in the valleys, especially in wintry showers, low cloud and gusty winds. Be prepared for severe wind chill and difficult navigation on high summits.
Weather
Generally cloudy with showers at times, which could be heavy with a risk of thunder in the afternoon. Any showers may fall as sleet or snow above 700m. A few bright intervals at times, mainly on low slopes in the northeast. Band of rain, with snow above 800m, spreads east overnight with summit gales developing.
Chance of cloud-free hill tops
40%, best chance in northeast.
Low cloud and visibility
Areas of cloud and fog above 700m, with patches on lower slopes, then cloud becoming patchier during the afternoon and lifting to higher slopes. Good visibility expected, though falling to moderate or poor in any showers.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
A band of heavy rain, with snow above 800m, will clear east in the early hours. A bright and cold day will follow with showers, wintry above 400m. Some could be heavy with hail and thunder.
Chance of cloud-free hill tops
20% overnight, becoming 70% by morning.
Maximum wind speed expected
Southeast 30 to 40mph gusts 55mph decreasing Southwest 15 to 20mph gusts 30mph by morning.
Temperature
- At 800m Plus 2C falling to Minus 1C.
- Valley Plus 4C.
- Freezing level Above summits, falling to 700m through the morning.
Low cloud and visibility
Extensive cloud above 500 or 600m overnight, clearing by dawn. Mainly good visibility between showers but becoming poor or very poor at times in wintry showers with occasional cloud above 500m.
Mountain weather information
Fri 5 Dec
Sunrise:
Sunset:
Dry and bright for much of the day and feeling cold. Rain spreads east later afternoon and evening, with a spell of snow. Southerly gales later with blizzards for a time on the summits. Freezing level 600m, rising above summits later.
Sat 6 Dec
Sunrise:
Sunset:
Unsettled with showers or longer spells of rain, perhaps some sleet or snow on high summits. A chance of strong winds. Freezing level above summits.
Sun 7 Dec
Sunrise:
Sunset:
Remaining unsettled with further rain or showers and a chance of strong winds. Freezing level above summits.
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.