Eryri / Snowdonia National Park
Includes all summits in the the northern half of Wales from Pumlumon northwards.
Sunday's Forecast
Severe gale or storm, mobility very difficult
Severe conditions on the mountains, any movement very challenging, you may be blown over. 55-70mph+
Heavy showers, snow and hail
Showery precipitation, often heavy, may merge to become constant for periods. A mix of snow and hail on higher terrain, rain or hail lower down. Risk of a rumble of thunder and isolated lightning.
Whiteout
Fog and lying snow over the mountains, possibly with falling or blowing snow, very disorientating. Map and compass essential, beware of unseen hazards such as cornices.
Chilly
Air temperature near or just above freezing on higher summits. Feeling distinctly chilly on tops when stationary or where exposed to wind. Take appropriate layers.
Winter kit required on higher mountains
Snow cover over higher mountain terrain. Safe progress around some tops and ridges will require suitable footwear - possibly crampons and ice-axe where necessary.
Click an icon for more information or click here for a key to all icons.
Severe gale or storm, mobility very difficult
Severe conditions on the mountains, any movement very challenging, you may be blown over. 55-70mph+
Heavy showers, snow and hail
Showery precipitation, often heavy, may merge to become constant for periods. A mix of snow and hail on higher terrain, rain or hail lower down. Risk of a rumble of thunder and isolated lightning.
Whiteout
Fog and lying snow over the mountains, possibly with falling or blowing snow, very disorientating. Map and compass essential, beware of unseen hazards such as cornices.
Chilly
Air temperature near or just above freezing on higher summits. Feeling distinctly chilly on tops when stationary or where exposed to wind. Take appropriate layers.
Winter kit required on higher mountains
Snow cover over higher mountain terrain. Safe progress around some tops and ridges will require suitable footwear - possibly crampons and ice-axe where necessary.
Viewing Forecast For
Eryri / Snowdonia National Park
Sunday 22nd December 2024
Last updated
Sat 21st Dec 24 at
12:03PM
Summary for all mountain areas
Very severe conditions due to widespread storm force northwesterly winds across the mountains. Frequent snow showers will come in off the sea, extending well inland and in some areas merging to give almost constant snow and whiteout for a few hours.
Headline for Eryri / Snowdonia National Park
Storm force upland wind. Frequent snow showers; chance thunder.
How windy? (On the summits)
Northwesterly 55 to 70mph; particularly gusty near precipitation.
Effect of the wind on you?
Arduous walking on lower slopes, whilst higher up severe wind chill and any mobility challenging, particularly near precipitation.
How Wet?
Frequent hail and snow; risk whiteout
Snow and hail showers, by afternoon sometimes frequent snow or the precipitation almost constant for an hour or two (giving whiteout); mostly rain valleys and lower slopes. Least precipitation mid Wales, where for periods dry.
Cloud on the hills?
Very extensive; cloud base varying
Near precipitation cloud sometimes below 400m particularly Snowdon range, but breaks to 750m, perhaps later fleeting breaks to higher tops or more widely mid Wales.
Chance of cloud free summits?
10%
Sunshine and air clarity?
Glimpses of sunshine. Very varied visibility, sometimes excellent, but appalling or perhaps near zero in snow/blowing snow.
How Cold? (at 900m)
-2C, slight rise through day. Will feel as cold as minus 18C directly in the wind.
Freezing Level
600m; will rise marginally through daylight.
Viewing Forecast For
Eryri / Snowdonia National Park
Monday 23rd December 2024
Last updated
Sat 21st Dec 24 at
12:03PM
How windy? (On the summits)
Northwesterly; 30mph.
Effect of the wind on you?
Anticipate periods of considerable wind chill and arduous walking.
How Wet?
Rain spreading east, probably afternoon
The odd shower, snow above 600m morning. Occasional rain, or possibly temporarily snow or refrozen rain above 650m, spreading slowly east middle of day or afternoon.
Cloud on the hills?
Deteriorating as cloud later envelops lower slopes
Cloud lifting off most summits for a few hours, although patches above about 750-900m. Into afternoon anticipate deterioration in rain: from west cloud filling in across the hills.
Chance of cloud free summits?
50% later dropping from west to 20%
Sunshine and air clarity?
Little or no sunshine as cloud thickens from west. Visibility very good; later poor in rain.
How Cold? (at 900m)
-1C, rising to near 2C by dusk. Will feel as cold as minus 9C directly in the wind.
Freezing Level
750m morning; will transition to above the summits by dusk.
Viewing Forecast For
Eryri / Snowdonia National Park
Tuesday 24th December 2024
Last updated
Sat 21st Dec 24 at
12:03PM
How windy? (On the summits)
Westerly 20-25 but on some slopes 30 to perhaps on Snowdon range 35mph.
Effect of the wind on you?
Often fairly small mid Wales but elsewhere, walking sometimes strenuous and wind chill considerable. Sudden gusts some lower slopes.
How Wet?
Drizzly, mainly west Wales
Drizzle frequent or perhaps in places almost constant western mountains. Elsewhere, drizzle now and again or rarely.
Cloud on the hills?
Blanket of cloud across even most lower slopes.
Cloud base widely below 300m western hills. Eastward, the cloud a little higher, but rarely above 600m.
Chance of cloud free summits?
Almost nil
Sunshine and air clarity?
Sunshine rarely coming through some valleys, mainly east Wales. Widely poor visibility, but very good or excellent easternmost Wales.
How Cold? (at 900m)
8C. Will feel as cold as minus 2C where exposed to the wind
Freezing Level
Above the summits.
Planning Outlook
A change in the weather pattern from Tuesday as high pressure progressively envelops Wales and England. Here (and also in S Scotland), extensively dry and the and progressively dropping, initially across Wales. Mild - although frost in valleys some nights. Still windy Scottish Highlands, here very mild with lying snow substantially melting. Rain frequent NW Highlands, and less so W Highlands. Further east little or no rain.