Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High confidence for the general synoptic pattern on Sunday with rain moving in later on, and also for the trend towards colder temperatures towards Christmas with easterly winds drawing in cold air. Lower confidence in cloud details for any particular day.
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.
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.
Mountain weather forecast
A murky day with hill fog likely, and some rain moving in overnight.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
20% | 20% | 10% | 20% | 20% | 70% |
Wind direction and speed (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
SE
25
|
SE
22
|
E
22
|
E
26
|
E
30
|
E
29
|
| 600m |
SE
17
|
SE
15
|
SE
16
|
E
17
|
E
20
|
E
20
|
| 300m |
SE
11
|
SE
10
|
SE
11
|
E
11
|
E
12
|
E
12
|
| Valley |
SE
11
|
SE
10
|
SE
11
|
E
11
|
E
12
|
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 | 26 | 26 | 31 | 36 | 35 |
| 600m | 20 | 19 | 19 | 23 | 28 | 28 |
| 300m | 19 | 19 | 18 | 21 | 23 | 24 |
| Valley | 19 | 19 | 18 | 20 | 22 | 23 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
3°
|
3°
|
3°
|
3°
|
3°
|
3°
|
| 600m |
5°
|
5°
|
5°
|
5°
|
5°
|
5°
|
| 300m |
6°
|
6°
|
7°
|
7°
|
7°
|
8°
|
| Valley |
8°
|
8°
|
8°
|
8°
|
8°
|
8°
|
| Freezing Level |
1,400m
|
1,300m
|
1,300m
|
1,400m
|
1,400m
|
1,400m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-4°
|
-3°
|
-3°
|
-3°
|
-4°
|
-3°
|
| 600m |
0°
|
0°
|
0°
|
0°
|
0°
|
1°
|
| 300m |
3°
|
4°
|
4°
|
4°
|
4°
|
4°
|
| Valley |
5°
|
5°
|
6°
|
6°
|
5°
|
5°
|
Additional weather information
Meteorologist's view
Quite a windy day on the summits, feeling cold in fresh or strong southeasterly winds, freezing level lifting above all summits. Murky with hill fog and outbreaks of light drizzle, which may last much of the day.
Weather
Cloudy with some light rain or drizzle possible, mist and hill fog through much of the day. Some outbreaks of rain moving in during the evening, possibly turning heavy at times. The best conditions will be towards the north and west of the area during the day.
Chance of cloud-free hill tops
50% in the west and north, 30% in the south and east.
Low cloud and visibility
Layers of scattered or broken low cloud above 100-200m are likely around Southern hills with cloud bases increasing and amounts decreasing further north and west, the cloud is associated with light rain and drizzle. Visibility will be moderate or poor at times in drizzle and hill fog on southeastern hills but will be mainly moderate in the north and west of the area.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Overnight rain clearing during the morning but remaining cloudy during the day, a few clearer spells further north and west. Perhaps some drizzly patches in the east.
Chance of cloud-free hill tops
50%, more low cloud around south and eastern hills.
Maximum wind speed expected
Southeasterly 20 gusts 25-35mph.
Temperature
- At 800m Plus 5 Celsius.
- Valley Plus 8 Celsius.
- Freezing level Above all summits
Low cloud and visibility
Scattered or broken layers of cloud above 400m for much of the day. Visibility moderate or poor at first but becoming good for most areas.
Mountain weather information
Tue 23 Dec
Sunrise:
Sunset:
Turning colder in freshening easterly winds. Quite a cloudy day especially for eastern mountains, with some persistent hill fog here, perhaps some brighter spells in the west. Some outbreaks of drizzle possible in the east too.
Wed 24 Dec
Sunrise:
Sunset:
A bitterly cold day with fresh or strong easterly winds, some winter sunshine likely but doing little for the cold feel, mainly good visibility with cloud above the hill tops.
Thu 25 Dec
Sunrise:
Sunset:
Remaining cold and a cloudy Christmas day, likely with strong easterly winds.
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.