Eryri / Snowdonia National Park
Includes all summits in the the northern half of Wales from Pumlumon northwards.
Thursday's Forecast
Windy, walking impeded
Blustery conditions enough to give buffeting on higher terrain or affect balance on exposed ridges. 25 to 40mph.
Sunshine and showers
A good amount of dry and bright weather, but scattered bursts of rain, some may be locally heavy.
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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Windy, walking impeded
Blustery conditions enough to give buffeting on higher terrain or affect balance on exposed ridges. 25 to 40mph.
Sunshine and showers
A good amount of dry and bright weather, but scattered bursts of rain, some may be locally heavy.
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
Thursday 17th September 2026
Last updated
Wed 16th Sep 26 at
4:00PM
Summary for all mountain areas
Strong westerly winds, gales widely on Scottish mountains; cool air and significant wind chill factor. Showery rain with heavy bursts mixed in most frequent in western Scotland, but tending to extend eastward. Showers develop more often for northern England too. Fewer showers for Wales after early rain clears.
Headline for Eryri / Snowdonia National Park
Windy, feeling cool; passing showers, most later.
How windy? (On the summits)
Westerly 25-30mph, easing in mid-Wales for a few hours; later strengthening, notably north, at times gusting 40mph highest tops.
Effect of the wind on you?
Blustery in exposure much of the day, buffeting gusts and a chilly feeling, and more strenuous walking late.
How Wet?
Scattered showers
A broad area of rain from overnight clears away southeast around dawn for a day of scattered showers. Many hills will see extended dry windows, but a period of more frequent showers afternoon.
Cloud on the hills?
Caps on summits with breaks
Cloud fairly extensive from overnight will break around or just before sunrise, to mostly just passing banks over the highest tops. A few lower patches form here and there around showers, more frequent afternoon.
Chance of cloud free summits?
60%, 40% afternoon
Sunshine and air clarity?
Mostly sunny on lower slopes, cloudier for a time afternoon. Good visibility, though some haze out over the Irish Sea.
How Cold? (at 900m)
6 or 7C, perhaps milder just at and before dawn. Feeling near freezing in direct wind.
Freezing Level
Above the summits.
Viewing Forecast For
Eryri / Snowdonia National Park
Friday 18th September 2026
Last updated
Wed 16th Sep 26 at
4:00PM
How windy? (On the summits)
Westerly 25-30mph early morning, shifting SW'ly and strengthening, to a gusty 40-50mph into afternoon.
Effect of the wind on you?
Increasingly strenuous walking, deteriorating during day to make walking arduous; notable wind chill.
How Wet?
Rain heavier into afternoon
A little spotty drizzle in the west in the morning, but mostly dry. Toward midday, patchy rain arrives from the west, heavier falls set in for a few hours afternoon, rain and drizzle continuing into evening.
Cloud on the hills?
Fairly extensive, window of improvement
Cloud shrouds west slopes, middle heights up, higher and more broken east. Cloud lifts, breaks up for a time but caps linger over tops. Through afternoon, will fill in more widely, 500m or lower on slopes facing Cardigan Bay; highest bases towards Carneddau.
Chance of cloud free summits?
40% lowering to 10%
Sunshine and air clarity?
Patchy sunshine early in day, becoming cloudy and dull afternoon. Hazy at best, visibility deteriorating afternoon.
How Cold? (at 900m)
7C, rising towards 9C afternoon and rising further evening into night. Feeling at or below 0C in direct wind.
Freezing Level
Above the summits.
Viewing Forecast For
Eryri / Snowdonia National Park
Saturday 19th September 2026
Last updated
Wed 16th Sep 26 at
4:00PM
How windy? (On the summits)
Southwesterly 35 to 45mph.
Effect of the wind on you?
Strenuous-to-arduous walking conditions, frequent buffeting on high exposed terrain. Considerable wind chill.
How Wet?
Light rain mostly west
Mostly light showery rain and drizzle but risk frequent over western hills. Patchier showers further east and northeastward.
Cloud on the hills?
May persist on high tops
Fairly extensive cloud over higher slopes, bases typically 600 to 800m, lowest in west in morning and in rain, tending to rise with time, some higher breaks north & east.
Chance of cloud free summits?
30%
Sunshine and air clarity?
Glimpses of sun, more common east Wales. Slight haze especially toward coasts, reduced in showers, better east.
How Cold? (at 900m)
7 to 9C, trending slightly cooler later in the daytime. Feeling like -2 to -5C directly in the wind.
Freezing Level
Above the summits.
Planning Outlook
Sustained gale-force winds continue extensively on the mountains into the weekend, southwesterly turning westerly with time. Frequent rain over western hills, showers passing eastwards, tending to fade during Sunday as higher pressure begins to build from the south, allowing wind speeds to lessen too over England & Wales. Warmer into early next week, though higher humidity brings more cloud some drizzly rain to the west. A generally more promising forecast for late September as high pressure nearby offers drier and warmer weather for more places. Weather systems grazing past Scotland to the north still bring locally stronger winds and occasional rain mainly to the northwest.