Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for the general story but some uncertainty in exact timings of weather fronts.
Mountain weather hazards
Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.
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.
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.
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.
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.
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
Severe and hazardous weather. Rain, heavy at times. Very windy with stormy conditions in the hills.
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
70% | 50% | 70% | 10% | 10% | 10% |
Wind direction and speed (mph)
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
S
62
|
S
66
|
S
65
|
SW
46
|
SW
36
|
SW
33
|
| 600m |
S
50
|
S
53
|
S
51
|
SW
33
|
SW
26
|
S
24
|
| 300m |
S
31
|
S
33
|
S
33
|
SW
23
|
S
17
|
S
16
|
| Valley |
S
31
|
S
34
|
S
33
|
SW
23
|
S
17
|
S
16
|
Wind gust (mph)
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m | 74 | 80 | 82 | 59 | 46 | 42 |
| 600m | 61 | 66 | 67 | 45 | 35 | 32 |
| 300m | 51 | 55 | 58 | 40 | 30 | 28 |
| Valley | 51 | 55 | 58 | 40 | 31 | 28 |
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
8°
|
6°
|
6°
|
4°
|
4°
|
4°
|
| 600m |
9°
|
8°
|
8°
|
6°
|
6°
|
6°
|
| 300m |
11°
|
11°
|
10°
|
8°
|
8°
|
8°
|
| Valley |
12°
|
12°
|
11°
|
10°
|
9°
|
9°
|
| Freezing Level |
2,300m
|
2,300m
|
2,000m
|
1,400m
|
1,300m
|
1,300m
|
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
0°
|
-2°
|
-1°
|
-4°
|
-3°
|
-3°
|
| 600m |
3°
|
2°
|
2°
|
0°
|
0°
|
0°
|
| 300m |
6°
|
6°
|
6°
|
4°
|
4°
|
4°
|
| Valley |
7°
|
7°
|
6°
|
6°
|
6°
|
6°
|
Additional weather information
Meteorologist's view
Widespread gales to low levels and gusts of 70 to 90mph will make progress almost impossible on higher slopes with a high risk of being blown over.
Weather
Outbreaks of rain, often heavy, and accompanied by very strong winds. Becoming drier and brighter during the afternoon with perhaps a few passing showers.
Chance of cloud-free hill tops
10% during the morning becoming 60% during the afternoon, 30% by midnight.
Low cloud and visibility
Poor visibility in rain with persistent cloud and fog above 500 or 600m. Visibility improving during the afternoon with cloud lifting but some areas of fog remaining above 600m, mainly in the west.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Mostly dry but the odd brief shower is possible. Rather cloudy at first then lengthening sunny spells developing during the morning. Cloud reforming during the evening to leave some clear spells, most likely in the northeast.
Chance of cloud-free hill tops
30% in morning becoming 80% in afternoon, 50% by midnight.
Maximum wind speed expected
Southwest 20 to 25mph gusts 35mph.
Temperature
- At 800m Plus 5 or 6 Celsius.
- Valley Plus 9 to 12 Celsius.
- Freezing level Above summits.
Low cloud and visibility
Areas of cloud above 500 or 600m in the morning, but higher and more broken in the northeast. Cloud lifting and breaking up through the afternoon. The visibility will be good away from low cloud.
Mountain weather information
Sun 23 Feb
Sunrise:
Sunset:
Severe conditions expected in the hills. Very strong winds reaching storm force even at fairly low levels. Heavy and persistent rain with a chance of flooding. Becoming showery through the afternoon. Freezing level well above summits.
Mon 24 Feb
Sunrise:
Sunset:
Sunny spells and a few, perhaps thundery, wintry showers. Feeling cold with a fresh southwesterly summit winds. Freezing level around summits.
Tue 25 Feb
Sunrise:
Sunset:
Sunny spells and blustery showers, wintry above 600m, some perhaps heavy and thundery. Strong, gusty northwesterly summit winds. Feeling cold at height with freezing level below 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.