Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for generally unsettled, mild and changeable weather through this period. Lower confidence for the timings of rain later Thursday and on Friday, then a lot of uncertainty in the detail of rain arriving over the weekend.
This evening forecast
Very strong southwest winds with gusts 60 to 80mph, but slowly easing later. Mainly dry with clear spells. A few showers arriving from the west around midnight, perhaps heavy and thundery. Freezing level above summits.
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.
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
Very windy with severe gales on the tops. A few heavy showers in morning then a dry and bright afternoon.
| 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) |
40% | 40% | 40% | 40% | 20% | 10% | 10% | 10% |
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 |
SW
47
|
SW
45
|
SW
48
|
SW
40
|
SW
38
|
SW
35
|
SW
38
|
SW
39
|
| 600m |
SW
32
|
SW
30
|
SW
32
|
SW
27
|
SW
27
|
SW
24
|
SW
24
|
SW
25
|
| 300m |
SW
18
|
SW
19
|
SW
19
|
SW
17
|
SW
18
|
SW
15
|
SW
15
|
SW
16
|
| Valley |
SW
19
|
SW
19
|
SW
20
|
SW
17
|
SW
19
|
SW
16
|
SW
15
|
SW
16
|
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 | 59 | 56 | 60 | 51 | 50 | 46 | 49 | 50 |
| 600m | 43 | 40 | 43 | 37 | 38 | 33 | 35 | 36 |
| 300m | 35 | 35 | 37 | 31 | 33 | 29 | 30 | 31 |
| Valley | 34 | 36 | 37 | 31 | 33 | 29 | 30 | 31 |
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
4°
|
4°
|
3°
|
3°
|
3°
|
3°
|
3°
|
3°
|
| 600m |
6°
|
6°
|
6°
|
5°
|
5°
|
5°
|
6°
|
6°
|
| 300m |
8°
|
8°
|
8°
|
8°
|
8°
|
8°
|
8°
|
8°
|
| Valley |
10°
|
10°
|
10°
|
9°
|
10°
|
9°
|
9°
|
9°
|
| Freezing Level |
1,400m
|
1,300m
|
1,300m
|
1,300m
|
1,300m
|
1,200m
|
1,200m
|
1,200m
|
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
-4°
|
-4°
|
-5°
|
-5°
|
-4°
|
-5°
|
-4°
|
-4°
|
| 600m |
0°
|
0°
|
0°
|
-1°
|
0°
|
0°
|
0°
|
0°
|
| 300m |
4°
|
4°
|
4°
|
4°
|
4°
|
4°
|
4°
|
4°
|
| Valley |
6°
|
6°
|
6°
|
6°
|
6°
|
6°
|
6°
|
6°
|
Additional weather information
Meteorologist's view
A mild day in the valleys but cold and very windy at height with gusts of 50 to 60mph making progress difficult. Hazardous conditions on exposed ridges and summits with a significant risk of being blown over.
Weather
A few showers overnight and in the morning, some heavy with a small risk of hail and thunder but moving through quickly. Some sunny spells between the showers, then becoming dry and mostly sunny in the afternoon. Dry with long clear spells in the evening.
Chance of cloud-free hill tops
70%, best chance in afternoon and evening.
Low cloud and visibility
Mostly good visibility but occasional cloud above 600m overnight and morning with poor visibility at times in showers. Cloud lifting in the afternoon with just isolated summit patches.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
A dry night with clear spells then staying dry during the day. High cloud will spread east through the afternoon then outbreaks of rain, heavy at times, developing during the evening.
Chance of cloud-free hill tops
70%, becoming 30% in the evening.
Maximum wind speed expected
South or Southwest 20 to 30mph gusts 40mph, increasing to gusts 50 to 60mph for a time.
Temperature
- At 800m Plus 3C rising to 6C.
- Valley Plus 5C rising to 11C.
- Freezing level Above summits.
Low cloud and visibility
Mainly good visibility during the day with just patchy summit cloud. Cloud lowering during the evening, becoming extensive above 600m with patches to lower slopes.
Mountain weather information
Fri 12 Dec
Sunrise:
Sunset:
Outbreaks of rain in the morning, clearing east then a bright afternoon with a chance of a few heavy showers. Light winds, becoming strong to gale force southerly in the evening. Freezing level above summits.
Sat 13 Dec
Sunrise:
Sunset:
A dry and bright morning and perhaps the afternoon too. Rain expected to spread east sometime, most likely late in the day or evening but low confidence at this stage. Southwest winds strengthening, gales later. Freezing level above summits.
Sun 14 Dec
Sunrise:
Sunset:
Spells of rain or drizzle with low cloud and gale force southwest winds. Very mild.
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.