Eryri / Snowdonia National Park
Includes all summits in the the northern half of Wales from Pumlumon northwards.
Sunday'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.
Frequent or persistent rain
Steady rain fairly persistent, occasionally heavy, rather wet underfoot.
Poor visibility
Murky conditions with areas of fog shrouding the hills, making navigation challenging. Map and compass essential.
Cool to mild
Air temperature 5 to 10C on higher terrain. Comfortable temperatures on lower terrain, but feeling chilly if exposed to wind higher up, especially if stationary. Pack extra layers.
Flooding
Fast-flowing rivers and streams. Some routes may be impassable due to flooding.
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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.
Frequent or persistent rain
Steady rain fairly persistent, occasionally heavy, rather wet underfoot.
Poor visibility
Murky conditions with areas of fog shrouding the hills, making navigation challenging. Map and compass essential.
Cool to mild
Air temperature 5 to 10C on higher terrain. Comfortable temperatures on lower terrain, but feeling chilly if exposed to wind higher up, especially if stationary. Pack extra layers.
Flooding
Fast-flowing rivers and streams. Some routes may be impassable due to flooding.
Viewing Forecast For
Eryri / Snowdonia National Park
Sunday 14th December 2025
Last updated
Sat 13th Dec 25 at
4:15PM
Summary for all mountain areas
Extensive rain, sustained heavy falls over many western mountains, expect flooding. Smaller amounts of rain toward the N/E Cairngorms, also S/E Wales and Peak District. Widespread gales, powerful gusts around high tops, locally downslope to east. Blanket cloud across hills, lowest in west.
Headline for Eryri / Snowdonia National Park
Gales, severe in places. Wettest toward west, low cloud.
How windy? (On the summits)
Southwesterly, 45-60mph, powerful gusts around high tops and in places downslope, tending to strengthen during daytime, reaching 70mph higher mountains.
Effect of the wind on you?
Arduous conditions over the hills. Strong gusty winds will challenge balance and stability all day, including less exposed slopes. Significant wind chill.
How Wet?
Rain frequent or persistent west; less east
Rain fairly persistent western hills, particularly Porthmadoc to Snowdon group, sometimes drizzly, but periods of steadier rain. Becoming constantly heavier onward into night. Patchier and smaller amounts eastward.
Cloud on the hills?
Extensive, lowest west
Cloud cloaks the high terrain of Snowdonia NP with bases down to middle western slopes, often to 500m or lower on/nearest Llyn peninsula. Higher bases from Berwyn group to Carneddau, but often covering tops.
Chance of cloud free summits?
20%
Sunshine and air clarity?
Sunshine unlikely; dull in west with haze near coast. Better visibility out of cloud east/north.
How Cold? (at 900m)
5 or 6C; little change with added height above 600m. Feeling like -5 to -8C in direct wind.
Freezing Level
Above the summits
Viewing Forecast For
Eryri / Snowdonia National Park
Monday 15th December 2025
Last updated
Sat 13th Dec 25 at
4:15PM
How windy? (On the summits)
Some uncertainty: Southwesterly 30-40mph from dawn, a possible easing to 20-25mph or less during daytime.
Effect of the wind on you?
Strenuous walking in the morning and perhaps all day; feeling chilly. May ease to small effects.
How Wet?
Rain most of the day, heavy west
Rain rarely ceasing widely, most persistent western slopes and high terrain of Snowdonia with heavy falls near the coast. Very wet underfoot, streams in spate, increasingly flooding.
Cloud on the hills?
Fairly extensive
Shrouding the mountains widely, lowest west where reaching lower slopes near to coasts. Highest bases toward north of A5, local breaks above 800m.
Chance of cloud free summits?
20%
Sunshine and air clarity?
Overcast and dull. Visibility mostly poor due to rain.
How Cold? (at 900m)
3 or 4C. Feeling like -5C in strongest early wind.
Freezing Level
Above the summits
Viewing Forecast For
Eryri / Snowdonia National Park
Tuesday 16th December 2025
Last updated
Sat 13th Dec 25 at
4:15PM
How windy? (On the summits)
Westerly 10 to 20mph.
Effect of the wind on you?
Fairly small.
How Wet?
Largely dry
Chance of an odd light shower mainly near to the west coast. Very wet underfoot following previous heavy rain, streams in spate, flooding.
Cloud on the hills?
Patchy cloud over tops
Patchy cloud banks most common nearer to coasts, may come and go above 600m, or 800m further inland. Breaks to tops more frequent hills near Bala.
Chance of cloud free summits?
40%
Sunshine and air clarity?
Occasional sun and thin high cloud. Visibility excellent out of cloud.
How Cold? (at 900m)
1 or 2C. Feeling like -4C directly in the breeze.
Freezing Level
Close to highest summits above 900m. Slight frost sheltered valleys in morning.
Planning Outlook
Prolonged rain will leave flooding of streams and rivers in many mountain areas early in the new week, with the exception of northeastern Scotland. A frontal system will eventually pass eastwards Monday-Tuesday, wind easing; dropping to freezing above 900m, beware of ice forming on higher Scottish mountains. Drier conditions for many on Tuesday, though showery near west coast of Scotland. By Wednesday, another system sweeps in from the Atlantic bringing further rain and gales. A risk of more heavy rain particularly England and Wales later in the week. A change of weather pattern is likely in the run up to Christmas, as high pressure builds northward, bringing drier weather, possibly chillier with time.