Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for mainly dry weather during this period but lower confidence in cloud amounts. High for bitterly cold, bright and windy conditions in the hills over Christmas.
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.
Mountain weather forecast
Low cloud and patchy drizzle. Cold and breezy on the tops.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
10% | 10% | <05% | <05% | <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 |
E
25
|
E
16
|
E
16
|
E
21
|
E
26
|
E
27
|
| 600m |
E
18
|
E
14
|
E
15
|
E
17
|
E
19
|
E
19
|
| 300m |
E
10
|
E
10
|
E
11
|
E
11
|
E
13
|
E
12
|
| Valley |
E
10
|
E
10
|
E
11
|
E
11
|
E
13
|
E
12
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 29 | 21 | 21 | 26 | 33 | 35 |
| 600m | 25 | 21 | 21 | 22 | 27 | 29 |
| 300m | 19 | 19 | 18 | 20 | 24 | 24 |
| Valley | 19 | 18 | 18 | 19 | 23 | 22 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
5°
|
5°
|
4°
|
3°
|
1°
|
0°
|
| 600m |
8°
|
8°
|
6°
|
5°
|
3°
|
2°
|
| 300m |
8°
|
8°
|
8°
|
6°
|
5°
|
4°
|
| Valley |
9°
|
9°
|
9°
|
8°
|
6°
|
5°
|
| Freezing Level |
2,000m
|
2,000m
|
2,000m
|
2,000m
|
1,800m
|
1,300m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-1°
|
1°
|
0°
|
-3°
|
-6°
|
-7°
|
| 600m |
4°
|
4°
|
3°
|
0°
|
-3°
|
-4°
|
| 300m |
5°
|
6°
|
5°
|
3°
|
1°
|
0°
|
| Valley |
6°
|
7°
|
6°
|
5°
|
2°
|
1°
|
Additional weather information
Meteorologist's view
Difficult conditions for navigation due to the extensive low cloud although conditions improving on low to mid slopes. Feeling rather cold on the tops, especially in exposure to the wind and in the damp conditions.
Weather
Extensive low cloud in the hills with occasional light drizzle. A few bright or clear intervals possible on low slopes in the west.
Chance of cloud-free hill tops
10% becoming 40% later.
Low cloud and visibility
Extensive cloud and fog down to low slopes at first. Cloud bases then lifting to around 600m in the afternoon with good visibility on lower slopes.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Remaining dry but feeling bitterly cold on the tops. Largely cloudy at first then cloud breaking up off the summits in the morning and lengthening sunny spells developing during the afternoon. Mostly clear skies in the evening. Strong and gusty winds with sudden gusts on lee slopes in the afternoon and evening.
Chance of cloud-free hill tops
20% becoming 90%.
Maximum wind speed expected
Easterly 25-35mph gusts 45mph, perhaps 55mph in afternoon.
Temperature
- At 800m Plus 1 Celsius falling to Minus 1 Celsius.
- Valley Plus 7 Celsius, falling to Plus 2 Celsius in evening.
- Freezing level 800m falling to 600m in afternoon then 400m in evening.
Low cloud and visibility
Extensive cloud above 400m at first then high summits becoming sunny above a cloud inversion. Most cloud clearing in the afternoon with mainly good visibility.
Mountain weather information
Thu 25 Dec
Sunrise:
Sunset:
Dry with some sunshine on Christmas day but feeling bitterly cold with a severe wind chill. Strong easterly winds: 25 to 35mph gusts 50mph. Freezing level 400m.
Fri 26 Dec
Sunrise:
Sunset:
Mainly dry and bright but cloud increasing through the day. Strong easterly winds easing. Freezing level 400m rising to 600m.
Sat 27 Dec
Sunrise:
Sunset:
Remaining dry and mostly cloudy. Continuing to feel cold with strong easterly winds. Feeling level rising to 800m.
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.