Eryri / Snowdonia National Park
Includes all summits in the the northern half of Wales from Pumlumon northwards.
Thursday's Forecast
Gale force, walking arduous
Considerable buffeting, walking into the wind will be strenuous on exposed terrain, stronger gusts may knock you off your feet. 40 to 55mph.
Heavy rain
Near-constant heavy rain, sometimes torrential over the mountains, very wet underfoot.
Poor visibility
Murky conditions with areas of fog shrouding the hills, making navigation challenging. Map and compass essential.
Chilly
Air temperature typically 0 to 5C on higher summits. Feeling distinctly chilly on tops when stationary or where exposed to wind. Take appropriate layers.
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Gale force, walking arduous
Considerable buffeting, walking into the wind will be strenuous on exposed terrain, stronger gusts may knock you off your feet. 40 to 55mph.
Heavy rain
Near-constant heavy rain, sometimes torrential over the mountains, very wet underfoot.
Poor visibility
Murky conditions with areas of fog shrouding the hills, making navigation challenging. Map and compass essential.
Chilly
Air temperature typically 0 to 5C on higher summits. Feeling distinctly chilly on tops when stationary or where exposed to wind. Take appropriate layers.
Viewing Forecast For
Eryri / Snowdonia National Park
Thursday 18th December 2025
Last updated
Wed 17th Dec 25 at
4:35PM
Summary for all mountain areas
Scotland: South to south-west gales bringing hill fog and showers, before band of heavy, perhaps squally, rain moves up from the southwest in afternoon, snow tops. England and Wales: Heavy rain spreading north with hill fog becoming extensive with strong to gale force southerly winds.
Headline for Eryri / Snowdonia National Park
Southerly gales with heavy rain soon setting in.
How windy? (On the summits)
Southerly 35 to 50mph, but direction and speed likely to vary, possibly lower speeds for periods during day.
Effect of the wind on you?
Expect arduous walking conditions and considerable wind chill on higher terrain, but may lessen for periods.
How Wet?
Heavy rain soon setting in
Dry possibly for a few hours from dawn, bar an odd patch of rain near west coast. Heavy rain moving in from south, possibly soon persistent. Breaking up into showery rain (also hail, snow high tops) evening into night.
Cloud on the hills?
Fairly extensive
Banks of cloud varying, most persistent south-facing slopes. Widely filling in if rain sets in. Best higher breaks Carneddau.
Chance of cloud free summits?
30% at first, dropping below 10%
Sunshine and air clarity?
Overcast and dull, murky in rain.
How Cold? (at 900m)
3 or 4C, then lowering to 0C into night. Wind chill feeling as cold as -10C on tops.
Freezing Level
Above the summits, then dropping into the night to around 900m.
Viewing Forecast For
Eryri / Snowdonia National Park
Friday 19th December 2025
Last updated
Wed 17th Dec 25 at
4:35PM
How windy? (On the summits)
Southwesterly 35 to 50mph, strongest northern tops in the morning, tending to lessen a little during day.
Effect of the wind on you?
Arduous conditions over higher mountains, frequent buffeting in exposure in morning. Significant wind chill.
How Wet?
Occasional showers with hail
Passing showers mostly morning, with hail briefly, falling as snow above 800m. Fading to be brief or rare afternoon.
Cloud on the hills?
Mostly high tops with breaks
Varying cloud bases, but often capping high tops above 800m in morning, some breaks more often afternoon. Clearer well inland and east Wales much of day.
Chance of cloud free summits?
50%
Sunshine and air clarity?
Bursts of sun, most frequent east. Visibility mostly very good.
How Cold? (at 900m)
0 to 2C. Feeling like -12C directly in the wind.
Freezing Level
900 to 1000m, rising slightly just above tops later or after dark.
Viewing Forecast For
Eryri / Snowdonia National Park
Saturday 20th December 2025
Last updated
Wed 17th Dec 25 at
4:35PM
How windy? (On the summits)
South to south-easterly 30 to 50mph, risk 60mph western hills at times.
Effect of the wind on you?
Walking arduous, or near west coast difficult, with a very turbulent airflow. Significant wind chill and buffeting.
How Wet?
Patchy rain, becoming persistent from west.
Patches of rain or drizzle here and there, may well become increasingly persistent from the west coast as front edges in. Very little in east and hills north of the A5.
Cloud on the hills?
Extensive
Cloud covering hills extensively, especially as rain moves in. Bases around 500-800m, lowest west coast. Higher bases at times north of the A5.
Chance of cloud free summits?
30%
Sunshine and air clarity?
Very likely overcast. Visibility good at times, but poor in rain.
How Cold? (at 900m)
2 or 3C
Freezing Level
Above the summits
Planning Outlook
South-southwesterly winds widely remain gale force over the mountains later this week and through into Saturday, severe upland gales for periods. Showery on Friday, most frequent in western Scotland with hail, also snow over tops. Another belt of persistent rain likely arrives onto western hills into Saturday, snow only highest Scottish tops. A switch to east-southeasterly winds by Sunday into early next week, some residual rain and high-level snow, but a drier theme develops and favouring chillier conditions into the Christmas period.