Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for a return to milder, unsettled conditions from mid-week. Medium in details.
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.
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.
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.
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
Rain and snow dying out. Perhaps some brighter spells developing later. Severe wind chill over the summits.
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
80% | 80% | 40% | 20% | 10% | <05% |
Wind direction and speed (mph)
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
NE
23
|
NE
21
|
NE
20
|
E
13
|
E
10
|
E
10
|
| 600m |
NE
13
|
NE
13
|
NE
13
|
E
8
|
E
8
|
E
9
|
| 300m |
NE
9
|
NE
9
|
NE
9
|
E
5
|
E
5
|
E
7
|
| Valley |
NE
9
|
NE
9
|
NE
9
|
E
5
|
E
5
|
SE
7
|
Wind gust (mph)
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m | 27 | 26 | 25 | 17 | 14 | 14 |
| 600m | 17 | 18 | 18 | 12 | 13 | 12 |
| 300m | 17 | 17 | 16 | 10 | 12 | 13 |
| Valley | 17 | 17 | 16 | 11 | 12 | 13 |
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
-1°
|
-1°
|
0°
|
0°
|
-1°
|
-1°
|
| 600m |
1°
|
1°
|
2°
|
2°
|
1°
|
1°
|
| 300m |
3°
|
4°
|
4°
|
4°
|
3°
|
2°
|
| Valley |
4°
|
5°
|
6°
|
6°
|
4°
|
3°
|
| Freezing Level |
700m
|
900m
|
900m
|
800m
|
800m
|
700m
|
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
-9°
|
-8°
|
-6°
|
-6°
|
-6°
|
-6°
|
| 600m |
-4°
|
-4°
|
-3°
|
-2°
|
-2°
|
-3°
|
| 300m |
0°
|
0°
|
1°
|
2°
|
0°
|
0°
|
| Valley |
1°
|
2°
|
3°
|
4°
|
2°
|
1°
|
Additional weather information
Meteorologist's view
Continuation of winter hazards at height, although snow dying out and winds gradually easing.
Weather
Outbreaks of rain and snow during the morning, snow mainly above 600m with temporary blizzard conditions and drifting over the summits. The rain and snow dying out late morning or early afternoon. Remaining mostly cloudy, although some brighter spells are possible in the afternoon, mainly in the west. Partly cloudy in the evening with a frost developing.
Chance of cloud-free hill tops
20% in the morning rising to 60% in the afternoon.
Low cloud and visibility
Extensive cloud, base around 300-600m in the morning. The cloud lifting and breaking a little in the afternoon to become occasional with base around 500-700m in the afternoon. Visibility moderate to very poor in early rain, snow and cloud, becoming occasionally good in the afternoon.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Patchy freezing fog possible in the valleys overnight, otherwise partly cloudy with a frost likely. Dry with some early brightness, but cloud tending to thicken and lower during the day along with strengthening south or southeast winds giving severe wind chill. Outbreaks of heavy rain and snow in the evening. Snow initially above 600m, temporary blizzard conditions possible, but turning to rain at all or most levels by midnight.
Chance of cloud-free hill tops
60% during daylight hours, decreasing 10% from late afternoon.
Maximum wind speed expected
Southeast 15mph, increasing to 35-40mph gusts 55mph.
Temperature
- At 800m Minus 1 Celsius, later Plus 2 Celsius
- Valley Minus 2 Celsius rising to plus 4 Celsius
- Freezing level All levels at first, gradually rising near or above the summits.
Low cloud and visibility
Occasional cloud, base 400-600m overnight, perhaps lifting and breaking briefly around the middle of the day. Cloud becoming extensive, base 300 to 600m from late afternoon. Visibility occasionally good, but moderate in rain and very poor in cloud and in hill snow during the evening.
Mountain weather information
Thu 7 Dec
Sunrise:
Sunset:
Cloudy and overcast with outbreaks of rain, heavy and persistent at times. South or southeast gales to perhaps storm force winds at height. Freezing level above the summits.
Fri 8 Dec
Sunrise:
Sunset:
Mostly cloudy with showers or longer outbreaks of rain, heavy at times. Strong to gale force southerly winds at height. Freezing level above the summits.
Sat 9 Dec
Sunrise:
Sunset:
Cloudy with showers or longer outbreaks of rain, heavy at times. Strong to gale force south or southwest winds at height. Freezing level above the 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.
The region can be divided into four areas with the northernmost area the most popular, including peaks such as Moel Hebog, Mynydd Mawr and the Nantlle Ridge. Many hikers tend to concentrate on Yr Wyddfa (Snowdon) itself regarding it as a fine mountain. However it can become quite crowded, with the peak welcoming around half a million visitors every year, of which four fifths scale the peak on foot, while the remainder choose to take the train instead.
One of Yr Wyddfa's (Snowdon) main attractions is the sheer number and variety of paths that reach the peak. This means that everyone from mountaineering novices to climbing experts should find a way up the mountain that will suit their abilities or provide them with a sufficient test. The easiest is the Llanberis path which, being the longest, has the most shallow ascent. In contrast, the Watkin Path is widely seen as being the most demanding ascent, despite also being considered the prettiest.