Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
Generally high confidence. Some uncertainty in persistence of heavy rain on Monday and timing of rain band Wednesday.
This evening forecast
Outbreaks of rain, falling as snow above 700-800m, gradually easing though the evening, with some snow down to 600m Dry by midnight. Strong northwest winds across the tops, gusting 50 mph on the higher summits, easing to 40 mph late evening. Freezing level 900m dropping to 700m towards midnight.
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.
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.
Mountain weather forecast
Dry morning with sunny spells, showers in the afternoon. Rain and gales late evening.
| 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) |
10% | <05% | <05% | <05% | 20% | 40% | 30% | 70% |
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 |
NW
27
|
NW
27
|
NW
25
|
W
17
|
SW
17
|
SW
23
|
SW
30
|
S
40
|
| 600m |
NW
17
|
NW
16
|
NW
15
|
W
10
|
SW
13
|
SW
16
|
S
22
|
S
29
|
| 300m |
NW
10
|
NW
10
|
NW
8
|
W
3
|
SW
9
|
SW
9
|
S
14
|
S
20
|
| Valley |
NW
12
|
NW
11
|
NW
10
|
W
4
|
SW
9
|
SW
9
|
S
13
|
S
19
|
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 | 34 | 34 | 32 | 21 | 23 | 30 | 40 | 54 |
| 600m | 23 | 23 | 22 | 15 | 18 | 23 | 31 | 42 |
| 300m | 21 | 20 | 19 | 9 | 16 | 19 | 26 | 37 |
| Valley | 23 | 22 | 20 | 10 | 15 | 18 | 24 | 35 |
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
-2°
|
-1°
|
-1°
|
-1°
|
0°
|
0°
|
1°
|
1°
|
| 600m |
1°
|
1°
|
1°
|
1°
|
2°
|
2°
|
3°
|
3°
|
| 300m |
3°
|
3°
|
3°
|
3°
|
5°
|
5°
|
5°
|
5°
|
| Valley |
4°
|
4°
|
4°
|
4°
|
6°
|
6°
|
6°
|
7°
|
| Freezing Level |
500m
|
500m
|
600m
|
600m
|
700m
|
800m
|
1,000m
|
1,200m
|
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
-10°
|
-9°
|
-8°
|
-7°
|
-6°
|
-7°
|
-7°
|
-7°
|
| 600m |
-5°
|
-5°
|
-4°
|
-3°
|
-2°
|
-3°
|
-3°
|
-3°
|
| 300m |
-1°
|
-1°
|
0°
|
1°
|
2°
|
2°
|
1°
|
0°
|
| Valley |
0°
|
1°
|
1°
|
2°
|
4°
|
3°
|
3°
|
2°
|
Additional weather information
Meteorologist's view
Increasing winds will give a notable chill. Note deteriorating conditions late evening and overnight with severe gales and heavy rain giving a risk of flooding.
Weather
Dry through the early hours and morning with clear then sunny spells. Cloud thickens around midday with a showers in the afternoon, falling as snow above 800m. Showers lighter and less frequent around dusk with snow confined to highest summits. Strengthening winds and rain spreads east late evening, turning heavy and persistent towards midnight.
Chance of cloud-free hill tops
90% or more in the morning. 60% in the afternoon. 10% in the evening.
Low cloud and visibility
Very good or excellent visibility with hills cloud free in the morning. Frequent cloud lowering to the 800-900m from midday. Visibility falling to poor through the evening and start of the night in increasingly heavy rain and cloud lowering to 500m.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Severe gales and heavy persistent rain through the early hours and much of the day with a risk of flooding. Winds easing after dusk, with rain easing late evening.
Chance of cloud-free hill tops
Nil
Maximum wind speed expected
South-southwest 45 gusting 55-60 mph, occasionally 65-70 mph across the highest summits early morning and possibly late afternoon. Easing to 20-25 mph in the evening.
Temperature
- At 800m Plus 6 Celsius rising to 8 Celsius
- Valley Plus 5 Celsius rising to 10 Celsius
- Freezing level Above the summits
Low cloud and visibility
Very poor visibility in persistent heavy rain and extensive cloud down to 400m.
Mountain weather information
Tue 2 Dec
Sunrise:
Sunset:
Overnight rain clears to a largely dry day with sunny spells, a few well scattered showers possible. Moderate southwest winds. Freezing level just above the summits.
Wed 3 Dec
Sunrise:
Sunset:
Generally cloudy with hill fog. Dry to start, but some showery rain for a time. Further rain possible in the evening. Moderate southwest winds. Freezing level above the summits.
Thu 4 Dec
Sunrise:
Sunset:
Strong southerly winds with heavy rain sweeping east. This clears to drier brighter conditions and lighter winds later in the day. Freezing level above the 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.