Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for the mobile nature of the westerly weather patterns through Tuesday then for high pressure extending from the northeast thereafter, but lowering for the transitional timing detail.
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
Rain and snow clearing to showers early afternoon. Strong to gale summit winds.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
30% | 90% | 80% | 60% | 60% | 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 |
SW
40
|
SW
48
|
W
37
|
W
38
|
W
40
|
W
39
|
| 600m |
S
28
|
SW
30
|
W
27
|
W
26
|
W
24
|
W
27
|
| 300m |
S
18
|
SW
20
|
W
18
|
W
18
|
W
15
|
W
18
|
| Valley |
S
18
|
SW
20
|
W
17
|
W
17
|
W
15
|
W
17
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 48 | 58 | 47 | 48 | 49 | 49 |
| 600m | 36 | 39 | 35 | 34 | 32 | 36 |
| 300m | 32 | 35 | 30 | 30 | 28 | 31 |
| Valley | 31 | 35 | 29 | 30 | 28 | 30 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
1°
|
2°
|
2°
|
1°
|
-1°
|
-2°
|
| 600m |
3°
|
4°
|
5°
|
4°
|
2°
|
1°
|
| 300m |
5°
|
6°
|
7°
|
6°
|
5°
|
4°
|
| Valley |
6°
|
7°
|
8°
|
8°
|
6°
|
5°
|
| Freezing Level |
1,200m
|
1,500m
|
1,200m
|
900m
|
800m
|
600m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-8°
|
-6°
|
-6°
|
-8°
|
-10°
|
-12°
|
| 600m |
-4°
|
-2°
|
-2°
|
-3°
|
-4°
|
-7°
|
| 300m |
0°
|
1°
|
3°
|
2°
|
0°
|
-2°
|
| Valley |
2°
|
3°
|
5°
|
4°
|
2°
|
0°
|
Additional weather information
Meteorologist's view
Gales becoming widespread for a time across most exposed ridges and summits.
Weather
Cloud thickening overnight to bring some patchy light rain and snow. A cloudy morning with patchy light snow, turning heavier and more persistent before mid-morning and increasingly to rain, before clearing to scattered showers early afternoon. Showers turning heavier during the early to mid-evening, bringing the chance of thunderstorms. Snow level 600m lifting above summits around dawn, lowering 600m again in early evening showers, then 400m from mid-evening.
Chance of cloud-free hill tops
20% at first, lowering 10% or less by mid-morning, then lifting 70% by mid-afternoon
Low cloud and visibility
Good or very good becoming moderate or poor in rain and showers, very poor in snow and within cloud, which will be quite extensive from 500m at first before lifting and breaking for the afternoon.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Beginning with brighter spells and only a few isolated showers, these wintry above 600m. Cloud soon thickening from the west to bring periods of light to moderate rain from late morning, which turns patchy by early evening. Strong to gale summit winds.
Chance of cloud-free hill tops
60% at dawn becoming 10% from late morning
Maximum wind speed expected
West or southwest mean 25-35mph, with gusts reaching 50mph across more exposed ridges and summits.
Temperature
- At 800m Zero Celsius at dawn increasing 4 Celsius for the afternoon
- Valley Plus 4 Celsius increasing 11 Celsius for the afternoon
- Freezing level 800m lifting above summits by midday
Low cloud and visibility
Good or very good becoming moderate or poor in rain and showers, very poor in early snow showers and within cloud, which becomes extensive from 500m from late morning.
Mountain weather information
Tue 17 Mar
Sunrise:
Sunset:
Cloudy with patchy rain and strong to gale summit winds. Freezing level above summits.
Wed 18 Mar
Sunrise:
Sunset:
Mainly dry with good sunny spells. Moderate winds. Freezing level above summits.
Thu 19 Mar
Sunrise:
Sunset:
Dry with bright and sunny spells. Light easterly 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.