Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
Only moderate confidence in rainfall detail into the day.
Mountain weather hazards
Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.
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.
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.
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.
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.
Mountain weather forecast
Fair weather to start. Rain developing during the afternoon. Fresh to strong summit winds later with temperatures falling and some snow at height.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
<05% | 10% | 40% | 70% | 90% | 90% |
Wind direction and speed (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
S
25
|
SE
22
|
S
14
|
W
11
|
N
18
|
N
28
|
| 600m |
S
17
|
SE
14
|
S
13
|
W
10
|
N
14
|
N
17
|
| 300m |
S
9
|
SE
8
|
S
8
|
W
6
|
N
11
|
N
14
|
| Valley |
S
9
|
SE
8
|
S
7
|
W
6
|
NW
11
|
N
13
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 29 | 25 | 17 | 14 | 24 | 39 |
| 600m | 22 | 19 | 16 | 13 | 20 | 25 |
| 300m | 21 | 16 | 13 | 9 | 19 | 24 |
| Valley | 21 | 16 | 12 | 9 | 19 | 23 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
6°
|
6°
|
7°
|
6°
|
2°
|
-1°
|
| 600m |
8°
|
9°
|
10°
|
8°
|
4°
|
1°
|
| 300m |
10°
|
11°
|
12°
|
9°
|
5°
|
4°
|
| Valley |
11°
|
12°
|
14°
|
10°
|
6°
|
5°
|
| Freezing Level |
1,800m
|
1,700m
|
1,700m
|
1,800m
|
1,800m
|
700m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
1°
|
1°
|
3°
|
3°
|
-4°
|
-9°
|
| 600m |
5°
|
6°
|
7°
|
5°
|
-1°
|
-4°
|
| 300m |
8°
|
9°
|
11°
|
7°
|
2°
|
-1°
|
| Valley |
9°
|
10°
|
12°
|
8°
|
3°
|
1°
|
Additional weather information
Meteorologist's view
A significant deterioration expected by the evening over the higher peaks as freezing levels fall and winds increase, care should be taken if heading out into the hills later in the day.
Weather
Dry, with some brightness to start the day. Cloud feeding from the west from late morning to limit any sunshine and bring some outbreaks of rain into the afternoon and evening. Rain mostly light initially but elevated showers may possibly bring the odd moderate or heavy spell, and there is a very low chance of an isolated rumble of thunder. Rain turning heavier and increasingly wintry into the evening as northerly winds strengthen and temperatures drop, increasingly turning to snow down to 500-600m.
Chance of cloud-free hill tops
80% becoming 10% by late afternoon
Low cloud and visibility
Cloud generally well above summits initially, thickening and lowering into the day to give areas of cloud with bases down to 400-700m in the west of the range by the late afternoon. Visibility generally moderate to good initially, somewhat hazy in general and perhaps reducing to briefly poor in any heavier spells of rain. Becoming increasingly poor or very poor at height into the day as conditions turn wintrier and hill fog increases.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Patchy rain at first, initially falling as snow above 600m. Clearing to largely dry and occasionally bright conditions for the afternoon. Summit winds strong at first.
Chance of cloud-free hill tops
10% becoming 75% for the afternoon
Maximum wind speed expected
North mean 25-30 mph during the morning, with gusts reaching 40mph across most exposed ridges and summits, before gradually easing through the afternoon
Temperature
- At 800m Minus 1 Celsius increasing 3 Celsius for the afternoon
- Valley Plus 4 Celsius increasing 10 Celsius for the afternoon
- Freezing level 700m lifting above summits from mid-morning
Low cloud and visibility
Good or very good becoming moderate or poor in rain, very poor in snow and within cloud, which will be extensive from 500m at first, before lifting and breaking during the rest of the day.
Mountain weather information
Sat 7 Mar
Sunrise:
Sunset:
A largely dry morning, with some limited brighter spells breaking through. Patchy light rain developing for the afternoon. Freezing level lifting above summits by mid-morning.
Sun 8 Mar
Sunrise:
Sunset:
Cloudy morning with occasional rain, though most of this should be light. Some brightness later. Fresh to strong summit winds. Freezing level above summits.
Mon 9 Mar
Sunrise:
Sunset:
Scattered light showers and limited brighter spells. Light to moderate 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.