Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
Usual uncertainties in distribution and organisation of showers. Small uncertainties around timing of rain on Tuesday. Moderate confidence for timing of rain on Wednesday.
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.
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.
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.
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
A chilly but bright start. Sunshine and scattered showers during the afternoon.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
10% | 10% | 40% | 40% | 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 |
S
14
|
S
17
|
SW
16
|
SW
16
|
SW
13
|
S
15
|
| 600m |
S
11
|
S
14
|
SW
14
|
SW
14
|
SW
12
|
S
10
|
| 300m |
SE
6
|
S
11
|
S
10
|
SW
10
|
S
7
|
SE
6
|
| Valley |
SE
6
|
S
10
|
SW
9
|
S
9
|
S
7
|
SE
6
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 18 | 21 | 20 | 21 | 17 | 18 |
| 600m | 16 | 19 | 19 | 19 | 16 | 13 |
| 300m | 14 | 17 | 17 | 17 | 13 | 11 |
| Valley | 14 | 17 | 15 | 15 | 11 | 11 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
1°
|
1°
|
2°
|
2°
|
1°
|
1°
|
| 600m |
3°
|
3°
|
4°
|
4°
|
4°
|
3°
|
| 300m |
5°
|
6°
|
7°
|
7°
|
7°
|
5°
|
| Valley |
6°
|
8°
|
9°
|
9°
|
8°
|
6°
|
| Freezing Level |
800m
|
900m
|
900m
|
900m
|
900m
|
900m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-4°
|
-5°
|
-4°
|
-3°
|
-4°
|
-5°
|
| 600m |
-1°
|
-1°
|
0°
|
0°
|
0°
|
-1°
|
| 300m |
3°
|
3°
|
4°
|
5°
|
4°
|
3°
|
| Valley |
4°
|
5°
|
7°
|
7°
|
6°
|
4°
|
Additional weather information
Meteorologist's view
A changeable day with sunshine and rainy spells, so light layers and waterproofs advised.
Weather
A chilly start with patchy grass frost. Some shallow mist and fog patches possible in prone valleys. This dissipating quickly after dawn. Winds much lighter than recent days though the risk of showers continues from late-morning into the afternoon. The showers will tend to be scattered across the park, and may turn heavy with a chance of hail and thunder. Plenty of sunny spells first thing, and in between any showers. Temperatures similar to Sunday but feeling a little warmer with lighter winds.
Chance of cloud-free hill tops
60% during the morning, otherwise 80%.
Low cloud and visibility
Patchy low cloud possible early on, otherwise cloud above summits. Cloud bases may drop briefly in any heavier downpours. Poor visibility to start in mist and fog, then becoming good or very good visibility outside of showers.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
A bright start in the far east of the park but turning wet from the west. Becoming breezier across summits. Often cloudy with patchy rain and drizzle during the morning which is likely to turn heavy and persistent by the evening. Cloud bases dropping low enough to bring some hill fog.
Chance of cloud-free hill tops
20% chance.
Maximum wind speed expected
South or southeasterly 25-30 mph, gusting 30-35mph at first. Winds increasing to 35-40mph, with gusts up to 40-45mph during the afternoon and evening.
Temperature
- At 800m Plus 6 Celsius rising to plus 13 Celsius.
- Valley Minus 1 Celsius rising to 12 Celsius.
- Freezing level Above summits.
Low cloud and visibility
Cloud bases around 400-500m but likely lower in heavy downpours bringing hill fog and poor visibility.
Mountain weather information
Wed 15 Apr
Sunrise:
Sunset:
Wet and windy with heavy outbreaks of rain creating very poor visibility across the park at times alongside low cloud bases. Turning drier later. Moderate to strong southerly winds. Freezing level above summits.
Thu 16 Apr
Sunrise:
Sunset:
Sunshine and showers. Feeling warm in the sunshine. Light southwesterly winds. Freezing level above summits.
Fri 17 Apr
Sunrise:
Sunset:
Mostly dry and bright with a risk of rain later. Light southerly 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.