Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
Confidence is moderate on Wednesday for detail of precipitation and cloud. High confidence for cold conditions to persist until Friday when a milder southwesterly airstream is expected to dominate towards the weekend.
This evening forecast
Cloud thickening during the evening but remaining dry, with strengthening southerly winds, feeling very cold on the hills.
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.
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.
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.
Mountain weather forecast
Cloudy with outbreaks of snow and sleet turning heavier later in the day, strong southeasterly winds, summit gales likely.
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
|
|
Chance of precipitation (at 800m) |
10% | 30% | 10% | 50% | 50% | 40% | 60% | 40% |
Wind direction and speed (mph)
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
E
47
|
SE
46
|
SE
46
|
SE
47
|
SE
42
|
E
41
|
E
38
|
E
37
|
| 600m |
SE
25
|
SE
28
|
SE
27
|
SE
29
|
SE
28
|
SE
27
|
E
24
|
E
22
|
| 300m |
SE
17
|
SE
21
|
SE
20
|
SE
23
|
SE
23
|
SE
22
|
E
20
|
E
18
|
| Valley |
SE
17
|
SE
20
|
SE
20
|
SE
23
|
SE
23
|
SE
22
|
SE
19
|
E
17
|
Wind gust (mph)
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m | 56 | 54 | 54 | 56 | 51 | 51 | 49 | 48 |
| 600m | 37 | 39 | 37 | 40 | 40 | 40 | 39 | 36 |
| 300m | 35 | 37 | 36 | 40 | 39 | 39 | 37 | 34 |
| Valley | 34 | 37 | 36 | 40 | 39 | 39 | 36 | 33 |
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
-5°
|
-5°
|
-5°
|
-4°
|
-4°
|
-3°
|
-4°
|
-4°
|
| 600m |
-2°
|
-2°
|
-2°
|
-2°
|
-1°
|
-1°
|
-1°
|
-2°
|
| 300m |
1°
|
0°
|
1°
|
1°
|
2°
|
2°
|
1°
|
1°
|
| Valley |
2°
|
2°
|
2°
|
3°
|
4°
|
4°
|
3°
|
2°
|
| Freezing Level |
0m
|
0m
|
200m
|
200m
|
300m
|
400m
|
300m
|
200m
|
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
-16°
|
-16°
|
-16°
|
-16°
|
-14°
|
-14°
|
-14°
|
-15°
|
| 600m |
-10°
|
-10°
|
-10°
|
-10°
|
-9°
|
-8°
|
-9°
|
-9°
|
| 300m |
-6°
|
-6°
|
-6°
|
-6°
|
-5°
|
-4°
|
-5°
|
-6°
|
| Valley |
-4°
|
-4°
|
-4°
|
-4°
|
-3°
|
-2°
|
-3°
|
-4°
|
Additional weather information
Meteorologist's view
Gales on the summits, possibly severe gale force gusts at times will give severe buffeting at times and enhance the windchill effect, combined with snowfall blizzard conditions are a risk on the higher mountains with some reasonable snow accumulations expected.
Weather
A cloudy start on Wednesday but mostly dry, cloud thickening during the morning with outbreaks of sleet and snow above 300m, rain at lower levels, Low cloud is likely to become a hazard as it becomes extensive during the morning. The snow and sleet will mostly be light and intermittent but turning heavier by late afternoon for a time. With strong winds and a risk of summit gales some blizzard conditions on the higher summits can be expected at times with accumulations expected, full winter gear is likely to be required on the hills.
Chance of cloud-free hill tops
50% reducing to 20%, cloud will become extensive at low levels during the morning.
Low cloud and visibility
Patchy cloud above 700m is a possibility in the morning but cloud will become more broken at lower levels during the morning with layers of cloud above 300m likely by lunchtime and during the afternoon. Visibility will be good in the early morning but turning moderate or poor in intermittent snow or sleet and very poor at times on the summits with white out conditions expected with snowfall and gales force gusts likely.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
A dry day with some sunny spells developing, feeling fresh in the easterly winds although these will be lighter than on Wednesday. Fresh snow may make walking progress tricky on the hills.
Chance of cloud-free hill tops
95%, most summits will be clear.
Maximum wind speed expected
Southeasterly 15-20mph
Temperature
- At 800m Minus 3 rising to minus 1 Celsius
- Valley Plus 1 rising to 5 Celsius.
- Freezing level 400m rising to 600m
Low cloud and visibility
Very little cloud below the summits expected, perhaps patches at times. Good or very good visibility is expected.
Mountain weather information
Fri 20 Feb
Sunrise:
Sunset:
Milder air will spread in from the southwest with plenty of cloud and outbreaks of rain on Friday morning, accompanied by southwesterly gales. Rain likely to ease later in the afternoon. Freezing level lifting from 600m to above all summits.
Sat 21 Feb
Sunrise:
Sunset:
Strong southwesterly winds will push in cloudy conditions and outbreaks of light rain and drizzle, rain clearing later in the day, low cloud likely to be a hazard. Freezing level above all summits.
Sun 22 Feb
Sunrise:
Sunset:
Outbreaks of rain and strong winds, possibility of gales, likely to continue later in the weekend with the risk of low cloud conditions, freezing level likely to be above all 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.