Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for unsettled, rather mild and often windy conditions through the coming week, but lower for timings of arrival and clearance of more persistent rain.
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.
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
Early showery rain then sunny spells and showers. Summit gales.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
30% | 10% | 20% | 20% | 20% | <05% |
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
43
|
SW
36
|
SW
35
|
SW
35
|
SW
32
|
S
29
|
| 600m |
SW
29
|
SW
23
|
SW
24
|
SW
24
|
S
22
|
S
20
|
| 300m |
SW
16
|
SW
13
|
SW
15
|
S
15
|
S
14
|
S
12
|
| Valley |
SW
16
|
SW
13
|
SW
16
|
S
15
|
S
14
|
S
12
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 50 | 42 | 43 | 43 | 39 | 35 |
| 600m | 35 | 28 | 32 | 32 | 29 | 26 |
| 300m | 30 | 26 | 27 | 28 | 26 | 23 |
| Valley | 30 | 26 | 28 | 28 | 26 | 23 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
5°
|
4°
|
5°
|
5°
|
5°
|
6°
|
| 600m |
7°
|
7°
|
7°
|
7°
|
7°
|
8°
|
| 300m |
9°
|
9°
|
9°
|
9°
|
9°
|
9°
|
| Valley |
10°
|
10°
|
11°
|
11°
|
10°
|
10°
|
| Freezing Level |
1,400m
|
1,300m
|
1,400m
|
1,500m
|
1,700m
|
1,900m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-3°
|
-2°
|
-2°
|
-2°
|
-1°
|
0°
|
| 600m |
1°
|
2°
|
2°
|
2°
|
2°
|
4°
|
| 300m |
6°
|
6°
|
6°
|
6°
|
6°
|
7°
|
| Valley |
7°
|
7°
|
8°
|
8°
|
7°
|
8°
|
Additional weather information
Meteorologist's view
Feeling cold at height with gusts around 40mph over ridges and summits.
Weather
A bright day on Monday with sunny spells and the odd shower, perhaps slightly wintry over highest summits. The showers gradually die out but cloud increases through the evening with outbreaks of occasionally heavy rain spreading quickly northeast towards midnight.
Chance of cloud-free hill tops
Around 40% at first soon becoming 75%, falling considerably during the evening.
Low cloud and visibility
Scattered bases around 600m in showers. Broken to overcast bases around 400m developing in evening rain across some areas of the Park. Visibility very good or excellent, but several kilometres in rain and near any showers.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Cloudy with occasionally heavy rain continuing through the early hours but tending to become lighter and patchier around dawn. Outbreaks of rain clear through the first half of the morning to leave sunny spells and blustery showers, with conditions underfoot likely to be very wet, with swollen water courses.
Chance of cloud-free hill tops
Close to zero at first gradually becoming 75% through the late morning and early afternoon.
Maximum wind speed expected
Southwesterly 60-70mph, with gusts around 80mph over ridges and summits.
Temperature
- At 800m Plus 6 to 9 degrees Celsius, falling to plus 3 Celsius after dusk
- Valley Around plus 8 degrees Celsius rising to plus 14 Celsius by early afternoon
- Freezing level Above the summits.
Low cloud and visibility
Periods or persistent cloud 400m, with patches below, at first gradually becoming more occasional above 600-750m through the late morning and early afternoon. Away from cloud, visibility very good or excellent, falling to several kilometres in rain and showers.
Mountain weather information
Wed 10 Dec
Sunrise:
Sunset:
Some sunny spells but generally rather a lot of cloud with occasional showers. Strong southwesterly winds, risk of summit gales. Freezing level above the summits.
Thu 11 Dec
Sunrise:
Sunset:
Bright start but cloud and outbreaks of occasionally heavy rain spreading east in morning. Strong southwesterly winds becoming more southerly and easing. Freezing levels above summits
Fri 12 Dec
Sunrise:
Sunset:
Cloudy with outbreaks of occasionally heavy rain. Fresh southerly 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.