Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for a change to cooler more changeable weather through Thursday, though low extending extent of coastal fog or low cloud, as well as some of the details regarding rainfall.
Mountain weather hazards
Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.
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
Cooler and more changeable weather, conditions turning brighter and more showery later.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
30% | 80% | 40% | 30% | 30% | 10% |
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
27
|
SW
24
|
W
28
|
W
28
|
W
29
|
W
26
|
| 600m |
S
24
|
SW
19
|
W
21
|
W
21
|
W
21
|
W
16
|
| 300m |
S
16
|
W
12
|
W
15
|
W
16
|
W
15
|
W
9
|
| Valley |
S
16
|
W
12
|
W
15
|
W
16
|
W
15
|
W
10
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 33 | 29 | 35 | 36 | 37 | 32 |
| 600m | 29 | 24 | 28 | 29 | 28 | 21 |
| 300m | 27 | 20 | 26 | 26 | 26 | 19 |
| Valley | 27 | 20 | 25 | 26 | 26 | 19 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
5°
|
5°
|
2°
|
1°
|
0°
|
-1°
|
| 600m |
6°
|
6°
|
5°
|
4°
|
3°
|
2°
|
| 300m |
8°
|
8°
|
8°
|
7°
|
6°
|
4°
|
| Valley |
9°
|
9°
|
10°
|
8°
|
7°
|
6°
|
| Freezing Level |
2,300m
|
2,100m
|
1,100m
|
800m
|
700m
|
600m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-1°
|
-1°
|
-4°
|
-7°
|
-8°
|
-8°
|
| 600m |
1°
|
2°
|
0°
|
-2°
|
-3°
|
-4°
|
| 300m |
4°
|
5°
|
4°
|
3°
|
1°
|
1°
|
| Valley |
5°
|
6°
|
6°
|
5°
|
3°
|
2°
|
Additional weather information
Meteorologist's view
Poor to start the morning due to low cloud and poor visibility, conditions are set to improve through the afternoon with good visibilities and views to distant mountains. Turning cooler through the afternoon with the introduction of colder air. This may bring some wind chill effects. Although conditions are turning brighter warm layers as well as sun protection are recommended.
Weather
Cloudy with mist and fog patches at low levels and in valleys likely at first. A band of cloud and rain will then push in from the west bringing extensive hill fog across the peaks as well as outbreaks of light patchy rain, this may fall as sleet or a mixture of snow and rain over the highest peaks. This is expected to gradually clear eastwards through the afternoon, leaving a brighter second half of the day with sunny spells and the odd scattered shower, once again potentially wintry over highest ground.
Chance of cloud-free hill tops
40% quickly falling to 20% for a time, gradually increasing to 70% by mid-afternoon.
Low cloud and visibility
Widespread low cloud and fog initially, up to 600-700m which has the potential to cover summits at times resulting in very poor visibility, this should clear by dawn. Cloud bases are then expected to lift to 400-600m through to midday, however still covering highest summits resulting in hill fog. Cloud will then become patchier from 800-1000m. Visibility becoming very good or excellent through the afternoon with a potential to drop lower in any showers, or within patchy cloud.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
A much colder start but dry initially with high cloud. Patchy cloud and rain are then expected to push in from the southwest through the morning, this may be wintry over the highest summits. This clears through the afternoon with some brighter breaks possible. A band of heavier and more persistent rain is likely overnight into Saturday.
Chance of cloud-free hill tops
80% dropping to 40% for a time through the morning and afternoon.
Maximum wind speed expected
Southwesterly or westerly 30-40mph gusting 35-45mph.
Temperature
- At 800m Minus 2 Celsius rising to Plus 1 Celsius.
- Valley Plus 4 Celsius rising to Plus 8 Celsius.
- Freezing level 600m gradually rising above summits.
Low cloud and visibility
Cloud generally above the summits, with patchy cloud down to 600-800m from mid-morning to early afternoon. Visibility generally very good outside of any patchy cloud and rain, which could drop visibilities to poor or very poor.
Mountain weather information
Sat 11 Apr
Sunrise:
Sunset:
Overnight persistent rain clearing eastward to leave a day of sunny spells and scattered showers, some of which may be heavy at times. Freezing level above summits.
Sun 12 Apr
Sunrise:
Sunset:
A chilly start with a continuation of sunny spells and scattered showers. Showers once again have the potential to be heavy at times, with a low risk of then falling as hail, the odd rumble of thunder is also possible. Freezing level above summits.
Mon 13 Apr
Sunrise:
Sunset:
Lower confidence, but generally a continuation of unsettled weather with further sunny spells and scattered showers, which may merge to give longer spells of rain. 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.