Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
Moderate regarding chance of heavy showers on Saturday. High for a dry day on Sunday and for settled conditions to dominate early next week. Low for cloud amounts from Tuesday.
Mountain weather hazards
Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.
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.
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
Scattered showers developing, locally heavy. Feeling cold on the tops.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
20% | 20% | 30% | 40% | 30% | 20% |
Wind direction and speed (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
W
23
|
W
20
|
W
20
|
NW
17
|
NW
16
|
NW
13
|
| 600m |
W
15
|
W
14
|
W
15
|
NW
12
|
NW
12
|
W
7
|
| 300m |
W
10
|
W
10
|
W
13
|
NW
9
|
NW
9
|
W
3
|
| Valley |
W
10
|
W
10
|
W
13
|
NW
9
|
NW
9
|
W
3
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 27 | 24 | 25 | 23 | 20 | 15 |
| 600m | 19 | 18 | 20 | 17 | 16 | 10 |
| 300m | 17 | 17 | 20 | 15 | 15 | 7 |
| Valley | 17 | 17 | 21 | 15 | 14 | 7 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
2°
|
2°
|
3°
|
3°
|
3°
|
2°
|
| 600m |
4°
|
4°
|
5°
|
6°
|
5°
|
4°
|
| 300m |
7°
|
7°
|
8°
|
9°
|
8°
|
6°
|
| Valley |
8°
|
8°
|
10°
|
10°
|
9°
|
7°
|
| Freezing Level |
1,100m
|
1,200m
|
1,100m
|
1,200m
|
1,100m
|
1,100m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-4°
|
-4°
|
-3°
|
-2°
|
-2°
|
-3°
|
| 600m |
0°
|
0°
|
1°
|
2°
|
1°
|
1°
|
| 300m |
4°
|
4°
|
5°
|
7°
|
5°
|
5°
|
| Valley |
5°
|
6°
|
7°
|
8°
|
7°
|
6°
|
Additional weather information
Meteorologist's view
Showers may develop quickly from late morning with sudden but brief downpours and a low risk of lightning and hail. Despite the risk of showers, most summits will clear of cloud with far reaching views of distant hills. Expect winds to be 10mph or more stronger over the summits and feeling below freezing, so extra layers are advised.
Weather
Mostly dry through the early hours with the outside chance of a rogue shower. Scattered showers quickly developing after dawn with a few heavy ones possible through the middle of the day, these transferring east through the afternoon before fading by the evening. The heaviest showers most likely in eastern areas with a low risk of thunder. Brief glimpses of sunshine in the morning with more prolonged sunny spells from midday.
Chance of cloud-free hill tops
20% west, 40% east. Becoming 80% by mid-afternoon.
Low cloud and visibility
Periods of cloud above 600-800m through the morning, most persistent in the west where patches may form from 500m upwards on west facing slopes. Lifting to patches above 850-950m through the afternoon with most summits clearing entirely of cloud. Often very good visibility with excellent air clarity, locally moderate in any heavier showers and very poor in cloud/hill fog through the morning.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Patchy frost and a few shallow mist/fog patches in the valleys around dawn and a very small chance of a light shower during the morning across the Snowdon Range and Carneddau. Otherwise, a generally dry day is expected with a mixture of patchy cloud and sunny periods, the sunshine prolonged at times.
Chance of cloud-free hill tops
80% becoming 100%.
Maximum wind speed expected
Northerly 25 mph.
Temperature
- At 800m Plus 1 Celsius becoming plus 8 Celsius.
- Valley Minus 1 Celsius rising to plus 13 Celsius by the afternoon.
- Freezing level 900m lifting above all the summits.
Low cloud and visibility
Periods above 900m at first, reducing to patches and lifting clear of all summits by mid-morning. Generally very good with excellent air clarity though locally very poor visibility in any fog/cloud.
Mountain weather information
Mon 20 Apr
Sunrise:
Sunset:
Morning sunshine giving way to cloudier skies with the odd light shower, falling as soft hail on the highest summits. Staying sunniest for longest in the far west. Freezing level around 950m and feeling cold on the summits in moderate to fresh northeasterly winds.
Tue 21 Apr
Sunrise:
Sunset:
A cloudier day is possible with hill fog at times and a greater chance of showers, though some places likely staying dry with sunny spells. Fresh to strong easterly or northeasterly winds giving a significant wind chill. Freezing level 800-1000m with showers wintry on summits.
Wed 22 Apr
Sunrise:
Sunset:
Likely dry with sunny periods and perhaps unbroken sunshine in places. Frost possible at first and again after dark with strong easterly winds on the summits. A significant wind chill. Freezing level 800-1000m.
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.