Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
A cold period of weather with potential for snow accumulations and very cold conditions on the hills. Strong winds will enhance the wind chill for the midweek period, becoming slightly milder towards the weekend. Lower confidence in details of the milder air arriving by the weekend. Keep an eye on the most up to date forecasts.
Mountain weather hazards
Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.
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.
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.
Blizzards
Blizzards and whiteouts present challenging and serious conditions due to a combination of falling or blowing snow, strong winds and cold temperatures. They can be highly disorientating, often resulting in near-zero visibility with limited or no visual references and no distinction between ground and sky. Cliff edges and cornices may not be apparent, even close up. These conditions require very good navigational skills.
Heavy Persistent Snow
Heavy snow can lead to rapid changes in underfoot conditions and paths may become treacherous or hidden. It also brings very poor visibility and often makes navigation much more challenging. When deep snow accumulates progress is often time consuming and strenuous, significantly affecting the distance one can travel on foot. Deep drifts can develop if snow is combined with strong winds. A heightened avalanche risk is possible and avalanche reports should be consulted where available.
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
Largely dry, bright conditions expected in daylight hours, although strong northerly winds continuing bringing a very cold feel and wintry showers continue in the west. Visibility generally very good.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
80% | 40% | 30% | 20% | 20% | 30% |
Wind direction and speed (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
N
43
|
N
42
|
N
38
|
N
36
|
N
33
|
N
32
|
| 600m |
N
31
|
N
27
|
N
27
|
N
26
|
N
22
|
N
18
|
| 300m |
N
21
|
N
18
|
N
19
|
N
17
|
N
14
|
N
11
|
| Valley |
N
21
|
N
18
|
N
19
|
N
18
|
N
14
|
N
12
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 50 | 50 | 46 | 44 | 40 | 39 |
| 600m | 38 | 34 | 35 | 34 | 30 | 26 |
| 300m | 35 | 31 | 32 | 30 | 27 | 24 |
| Valley | 35 | 32 | 32 | 30 | 27 | 25 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-3°
|
-3°
|
-3°
|
-3°
|
-3°
|
-3°
|
| 600m |
0°
|
0°
|
0°
|
0°
|
0°
|
-1°
|
| 300m |
2°
|
2°
|
3°
|
2°
|
2°
|
1°
|
| Valley |
4°
|
4°
|
4°
|
4°
|
3°
|
3°
|
| Freezing Level |
400m
|
300m
|
300m
|
200m
|
200m
|
100m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-14°
|
-13°
|
-13°
|
-13°
|
-12°
|
-12°
|
| 600m |
-9°
|
-8°
|
-8°
|
-8°
|
-7°
|
-7°
|
| 300m |
-4°
|
-3°
|
-3°
|
-3°
|
-3°
|
-3°
|
| Valley |
-2°
|
-1°
|
-1°
|
-1°
|
-2°
|
-2°
|
Additional weather information
Meteorologist's view
A very cold day expected on the hills despite sunshine during the afternoon, with a very significant wind-chill factor at height. Any morning snow accumulations likely to be somewhat persistent.
Weather
Snowfall in the early hours above around 200m will lead to accumulations and drifting of snow in places overnight. Precipitation will clear towards dawn however with skies increasingly clearing into the morning. During daylight hours generally bright conditions expected, but occasional wintry showers will affect the west of the range, these becoming most likely towards the west coast. Showers wintry to relatively low levels with hail also likely. Winds will continue to be strong, gales possible on the higher summits, with a very cold feel to the day, alongside fresh snow accumulations, making conditions quite treacherous. Skies remaining clear into the evening with a severe frost expected and any lying snowpack likely to harden.
Chance of cloud-free hill tops
20% initially, becoming 80% from late morning as early cloud lifts and clears.
Low cloud and visibility
Widespread cloud above around 500-700m initially, this will lift and clear during the morning with patchy cloud cover during daylight hours. Visibility moderate to very poor initially, become excellent into the day outside of showers.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
A largely dry, sunny day expected. Remaining very cold however with a hard frost overnight and temperatures reaching only low single digits maximum by day with fresh north or north-westerly winds continuing.
Chance of cloud-free hill tops
95%, patchy cloud around summits in the afternoon.
Maximum wind speed expected
Northerly 25-30mph gusts 35-40mph.
Temperature
- At 800m Minus 5 rising to Minus 2.
- Valley Minus 3 rising to Plus 3 Celsius.
- Freezing level Surface level.
Low cloud and visibility
Perhaps some patchy cloud around 800m at times. Very good or excellent visibility expected.
Mountain weather information
Fri 21 Nov
Sunrise:
Sunset:
Remaining cold in the northerly airflow, otherwise dry, bright and sunny, fresh north westerly winds backing south-westerly later in the day. Freezing level 200m rising to 500m later in the day.
Sat 22 Nov
Sunrise:
Sunset:
Southerly winds will introduce slightly milder air and some precipitation, the mix of snow/sleet and rain is uncertain at this time. Freezing level around 1000m, low confidence.
Sun 23 Nov
Sunrise:
Sunset:
Expected to remain chilly with cloudier conditions and southerly winds, low confidence in the detail for later in the weekend.
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.