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.
Heavy rain
Near-constant heavy rain, sometimes torrential over the mountains, very wet underfoot.
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.
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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.
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.
Viewing Forecast For
Eryri / Snowdonia National Park
Sunday 27th September 2026
Last updated
Sat 26th Sep 26 at
4:30PM
Summary for all mountain areas
Southerly winds up to gale-force on high terrain, including a swathe of particularly powerful winds and gusts moving across England & Wales during the day. Rain generally sets in from the west with some heavy falls, a band of more intense rain for a time. Cloud increasingly covering many hills.
Headline for Eryri / Snowdonia National Park
Soon gales and severe gusts, rain moves in heavier.
How windy? (On the summits)
Southerly 40mph soon from dawn, rising during morning, abruptly reaching 50-60mph, violent gusts over 70mph in places for an hour or so late morning to middle of day. Then W-SW'ly lessening quickly in afternoon to 30mph, later 20mph.
Effect of the wind on you?
Increasingly difficult mobility over exposed terrain in the morning, challenging gusts widely for a few hours; notable wind chill. Then improving afternoon to become smaller later in day.
How Wet?
Heavy thundery rain for a time
Mostly dry start, then rain develops quickly, setting in for several hours, a swathe of heavy rain likely into middle of day, briefly torrential, risk thunder. Breaking into showers afternoon, mostly in west. Drier toward evening.
Cloud on the hills?
Clear early hours, then covering high terrain
Little or no cloud on hills at first. Patches starting to lower onto tops, suddenly filling in over high terrain afternoon, and lowering towards 500m locally during heaviest rain. Lifting again later.
Chance of cloud free summits?
80% lowering to 20% in rain
Sunshine and air clarity?
Early weak sun soon gives way to overcast skies; brightening up again later in day. Very good visibility, deteriorating with cloud/rain, poor for a time.
How Cold? (at 900m)
9 or 10C, rising a degree afternoon, then notably cooling into night. Feeling like 0C in direct wind.
Freezing Level
Above the summits.
Viewing Forecast For
Eryri / Snowdonia National Park
Monday 28th September 2026
Last updated
Sat 26th Sep 26 at
4:30PM
How windy? (On the summits)
West-southwesterly 10 to 20mph, strongest on northern tops in morning.
Effect of the wind on you?
Mostly small.
How Wet?
Rain unlikely
Cloud on the hills?
Local patches lift and clear
Some patchy cloud in the morning mainly on south-facing slopes near to coasts, plus local mist in some valleys around dawn inland. All lifting and dispersing for clear hills.
Chance of cloud free summits?
80%
Sunshine and air clarity?
Patchwork of cloud and sun; some early cloud in west, becoming sunnier near coast with time. Visibility excellent.
How Cold? (at 900m)
6C rising to 9C.
Freezing Level
Above the summits.
Viewing Forecast For
Eryri / Snowdonia National Park
Tuesday 29th September 2026
Last updated
Sat 26th Sep 26 at
4:30PM
How windy? (On the summits)
Southeasterly 40 to 60mph, turbulent gusts around high tops, passes and downslope.
Effect of the wind on you?
Challenging walking conditions on exposed terrain, but sudden buffeting also to some lower elevations.
How Wet?
Some drizzle, rain on and off
Spots of rain from time to time, drizzly where in cloud; some pulses of rain spreading from the south, may become more constant falls on hills toward and west of Porthmadog.
Cloud on the hills?
Most persistent eastern hills
Banks of cloud most persistent over east and mid Wales, may cling around tops much of the day. Higher and more broken cloud north and northwestern areas. May tend to thin and disperse during day.
Chance of cloud free summits?
40%
Sunshine and air clarity?
Some glimpses of weak sun through high cloud mostly northwest coastal areas. Hazy.
How Cold? (at 900m)
12 to 14C, feeling humid; then only slight drop onward into night.
Freezing Level
Above the summits.
Planning Outlook
A changeable prospect during the week ahead. A better day on Monday as higher pressure expands in from the south, but showers and brisk winds continue toward northwest Scotland. Strong southeasterly winds by Tuesday, widely gales on mountains with turbulent downslope gusts toward the west; a risk of rain developing from the south during the day, becoming heavy later. Blustery south-southwesterlies into Wednesday and Thursday, showery in the west. Higher pressure tends to expand further north again into early October. Mostly mild temperatures.