Eryri / Snowdonia National Park
Includes all summits in the the northern half of Wales from Pumlumon northwards.
Friday'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.
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.
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.
Viewing Forecast For
Eryri / Snowdonia National Park
Friday 18th September 2026
Last updated
Thu 17th Sep 26 at
4:22PM
Summary for all mountain areas
Already windy with light showery rain over western hills early in the day, but conditions will worsen from the west as gales strengthen and rain / drizzle becomes persistent, some heavier rain; cloud bases lower to widely blanket hills, lowest in west.
Headline for Eryri / Snowdonia National Park
Windy, strengthening gales; persistent heavy rain develops.
How windy? (On the summits)
Westerly 25-30mph early morning, shifting southwesterly and strengthening rapidly middle of day into afternoon to 50mph, reaching 60mph higher tops in Snowdon group with stronger gusts in places.
Effect of the wind on you?
Increasingly strenuous walking, deteriorating during day to become arduous on high terrain, in places difficult with considerable wind chill; powerful gusts giving buffeting toward some lower slopes.
How Wet?
Rain develops and sets in, sustained heavier falls
A little spotty drizzle in the west in the morning, but mostly dry for a few hours. Toward midday, patchy rain arrives from the west, prolonged heavy rain sets in through afternoon into evening, rain and drizzle continuing into night. Increasingly wet underfoot, streams rising.
Cloud on the hills?
Fairly extensive, window of improvement, then lowering widely
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, 400-500m 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 weak sunshine early in day, high cloud thickening to be overcast and dull. Hazy at best, visibility deteriorating to poor afternoon.
How Cold? (at 900m)
7C, rising towards 9C afternoon, reaching 11C by evening, little change after dark; becoming more humid. 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
Thu 17th Sep 26 at
4:22PM
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, most frequent over western hills, possibly steadier rain for a few hours in morning. 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 rain, 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.
Viewing Forecast For
Eryri / Snowdonia National Park
Sunday 20th September 2026
Last updated
Thu 17th Sep 26 at
4:22PM
How windy? (On the summits)
Westerly 25-35mph early morning, tending to ease to 20mph.
Effect of the wind on you?
Blustery and chilly early in the day, affecting comfortable walking and balance on exposed tops, moderating.
How Wet?
Little or no rain
Local drizzly showers possible over coastal hills early in day, but mostly dry. Toward evening, drizzly rain may return from the west.
Cloud on the hills?
Lifting and clearing, lowers later
Patchy cloud above 700-800m in morning, most common near west coast. Lifting and clearing, but patches may come and go on higher western tops. If drizzle develops, cloud lowering back onto hills later.
Chance of cloud free summits?
60%
Sunshine and air clarity?
Broken cloud and sunshine; high cloud tends to thicken to cover the sky. Some haze especially morning and evening, visibility very good for a time.
How Cold? (at 900m)
6 or 7C, little change all day, then tending to rise onward into night. Feeling sub-zero in early wind.
Freezing Level
Above the summits.
Planning Outlook
Gale-force southwesterly winds continue extensively on the mountains into Saturday and early Sunday. 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.