Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High confidence in the unsettled conditions continuing the rest of this week, but considerable uncertainty on the extent of rainfall expected over the area this weekend.
This evening forecast
Showery outbreaks of rain and a risk of snow on summits for a time, clearing through the evening. Strong winds with gales at height.
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.
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.
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 bright but windy day with gales at height and occasional showers.
| 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) |
40% | 40% | 40% | 40% | 40% | 30% | 30% | 30% |
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
42
|
SW
44
|
SW
43
|
SW
36
|
SW
34
|
SW
33
|
SW
31
|
SW
30
|
| 600m |
SW
26
|
SW
29
|
SW
28
|
SW
25
|
SW
24
|
SW
21
|
SW
20
|
SW
20
|
| 300m |
SW
16
|
SW
17
|
SW
18
|
SW
16
|
SW
16
|
SW
13
|
SW
12
|
S
11
|
| Valley |
SW
16
|
SW
18
|
SW
19
|
SW
16
|
SW
17
|
SW
13
|
SW
11
|
S
11
|
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 | 51 | 54 | 53 | 45 | 43 | 41 | 39 | 39 |
| 600m | 35 | 38 | 38 | 33 | 33 | 29 | 28 | 28 |
| 300m | 31 | 33 | 33 | 29 | 29 | 25 | 25 | 23 |
| Valley | 31 | 34 | 34 | 29 | 29 | 24 | 24 | 22 |
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
0°
|
1°
|
2°
|
2°
|
2°
|
2°
|
2°
|
2°
|
| 600m |
3°
|
4°
|
4°
|
4°
|
4°
|
4°
|
4°
|
4°
|
| 300m |
5°
|
6°
|
6°
|
6°
|
7°
|
7°
|
6°
|
6°
|
| Valley |
6°
|
8°
|
8°
|
8°
|
9°
|
8°
|
7°
|
7°
|
| Freezing Level |
900m
|
1,000m
|
1,100m
|
1,100m
|
1,100m
|
1,100m
|
1,100m
|
1,100m
|
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
-9°
|
-8°
|
-7°
|
-6°
|
-6°
|
-6°
|
-6°
|
-5°
|
| 600m |
-4°
|
-3°
|
-2°
|
-2°
|
-2°
|
-1°
|
-1°
|
-1°
|
| 300m |
0°
|
2°
|
2°
|
2°
|
3°
|
3°
|
3°
|
3°
|
| Valley |
2°
|
4°
|
4°
|
4°
|
5°
|
5°
|
4°
|
4°
|
Additional weather information
Meteorologist's view
Gusts up to around 50mph at height will give difficult walking conditions with a significant risk of being blown off balance. Also note the significant wind chill.
Weather
A very blusterly day with a few showers, these wintry above 800m and possibly heavy with hail and the odd rumble of thunder in the morning. Best of the sunnier spells in the afternoon. Gales on upper slopes.
Chance of cloud-free hill tops
60% in the morning, rising to 80% in the afternoon.
Low cloud and visibility
Visibility will be generally good, but occasionally deteriorating to a few kilometres or worse in showers alongside patches of low cloud down to 600-700m.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
A mainly dry day with some sunshine but also a few patches of hill fog which may linger. Cloud will tend to increase later and bring the risk of showery rain late afternoon or evening. Remaining windy with gales at height.
Chance of cloud-free hill tops
60%.
Maximum wind speed expected
Gusting 40-50mph on summit and ridges.
Temperature
- At 800m Plus 3 Celsius.
- Valley Plus 4 rising 9 Celsius.
- Freezing level 1200m.
Low cloud and visibility
A few patches of low cloud with bases above 600m lingering on some upslopes, but some clear breaks too, especially across northern areas.
Mountain weather information
Sun 21 Dec
Sunrise:
Sunset:
Cloudy with outbreaks of rain, possibly heavy at times. Strong summit winds. Freezing level above summits.
Mon 22 Dec
Sunrise:
Sunset:
Another rather cloudy day with spells of rain, but some drier, brighter conditions developing. Moderate to fresh summit winds and freezing level above summits.
Tue 23 Dec
Sunrise:
Sunset:
Variable amounts of cloud and generally dry. Moderate to fresh summit wind. Freezing level 1000m.
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.