Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High in unsettled weather tomorrow associated with Storm Dave, but moderate in some of the details relating to wind speeds and rainfall. High for return to more settled weather thereafter.
This evening forecast
Potential for some cloud breaks to end the day with shower risk dying out.
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.
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.
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.
Strong Sunlight
Harmful UV levels from sunlight increase with altitude giving a greater risk of sunburn and eye damage, even on some overcast days. On breezy days, the cooling effect of wind on exposed skin may disguise any feeling of sunburn until it is too late. If there is snow cover, glare increases the effect of UV rays especially on the eyes. It is advisable to wear sun block, protective clothing such as a long-sleeved top and hat and have good quality eye protection.
Mountain weather forecast
Strom Dave bringing serve gale or storm force winds through Saturday.
| 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) |
<05% | <05% | <05% | 10% | 30% | 40% | 70% | 40% |
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 |
W
26
|
W
17
|
S
14
|
S
34
|
S
48
|
S
54
|
SW
60
|
SW
56
|
| 600m |
W
15
|
SW
10
|
S
10
|
S
24
|
S
35
|
S
39
|
S
45
|
SW
40
|
| 300m |
W
9
|
SW
5
|
S
6
|
SE
16
|
S
25
|
S
27
|
S
30
|
SW
27
|
| Valley |
W
9
|
SW
5
|
S
6
|
SE
16
|
S
24
|
S
26
|
S
28
|
SW
25
|
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 | 32 | 21 | 18 | 42 | 61 | 69 | 78 | 74 |
| 600m | 21 | 14 | 14 | 32 | 48 | 54 | 62 | 57 |
| 300m | 19 | 12 | 11 | 26 | 43 | 47 | 53 | 49 |
| Valley | 19 | 11 | 11 | 26 | 42 | 46 | 51 | 46 |
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°
|
-1°
|
1°
|
4°
|
4°
|
4°
|
1°
|
| 600m |
2°
|
2°
|
2°
|
4°
|
7°
|
6°
|
6°
|
4°
|
| 300m |
5°
|
4°
|
4°
|
6°
|
9°
|
8°
|
8°
|
6°
|
| Valley |
6°
|
5°
|
5°
|
7°
|
11°
|
10°
|
10°
|
8°
|
| Freezing Level |
700m
|
600m
|
600m
|
1,500m
|
1,500m
|
1,400m
|
1,700m
|
900m
|
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
-8°
|
-7°
|
-6°
|
-6°
|
-3°
|
-5°
|
-5°
|
-9°
|
| 600m |
-3°
|
-3°
|
-2°
|
-2°
|
1°
|
-1°
|
-1°
|
-4°
|
| 300m |
1°
|
2°
|
2°
|
2°
|
5°
|
4°
|
3°
|
1°
|
| Valley |
3°
|
3°
|
3°
|
4°
|
7°
|
6°
|
5°
|
3°
|
Additional weather information
Meteorologist's view
Severe winds on summits with the potential for gusts to increase slightly earlier than in the table above, this will lead to challenging walking conditions, with the potential to knock people off their feet. Navigation may also be challenging at times through the morning period due to patchy low cloud and hill fog.
Weather
Cloud increasing through the morning with outbreaks of patchy rain and drizzle likely. Rain then turns more showery in nature with low level cloud becoming patchier, and perhaps a few bright or sunny spells developing. A second band of more persistent and potentially heavier rain is likely through the evening.
Chance of cloud-free hill tops
40% decreasing to 20% for a time through the morning.
Low cloud and visibility
Cloud initially above summits with periods of cloud at 700-900m. Cloud bases rising above summits through the afternoon, with patches of cloud down to 700-900m in any passing showers. Very good visibility in general but poor in drizzle and very poor in cloud with patchy hill fog at times through the morning.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
A much colder day ahead for Sunday but with drier and brighter conditions. Patchy cloud likely throughout the day, with the risk of showers remaining, mainly through the morning. Remaining windy with gales likely on summits.
Chance of cloud-free hill tops
60% gradually rising to 80% from afternoon onward.
Maximum wind speed expected
Westerly 40-50 mph.
Temperature
- At 800m Minus 1 Celsius rising to plus 1 Celsius.
- Valley Plus 4 Celsius rising to plus 8 Celsius.
- Freezing level At Summits, rising at times.
Low cloud and visibility
Cloud bases generally above summits with patchy cloud at 700-1000m covering summits at times through the morning. Very good visibility in general may becoming poor in showers and very poor in low cloud or hill fog.
Mountain weather information
Mon 6 Apr
Sunrise:
Sunset:
Dry with increasing amounts of sunshine giving excellent visibilities. Fresh to strong southerly or southeasterly winds but not feeling as cold. Moderate UV levels. Freezing levels above the summits.
Tue 7 Apr
Sunrise:
Sunset:
Dry with plenty of sunshine to start the day, turning increasingly cloudy through the afternoon with the potential for the odd show as dusk approaches. Fresh to strong southeasterly winds.
Wed 8 Apr
Sunrise:
Sunset:
A cloudier day ahead with the potential for some showery outbreaks later in the day. Moderate to strong southwesterly 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.