Snowdonia National Park
Includes all summits in the the northern half of Wales from Plynlimon northwards.
Viewing Forecast For
Snowdonia National Park
Monday 20th September 2021
Last updated
Sun 19th Sep 21 at
3:49PM
Summary for all mountain areas
Low cloud and generally damp conditions will affect western Scotland. Total rainfall small, although some steadier rain will develop as a front moves in. SW'ly winds strongest in the far north. Elsewhere a fine day with broken cloud and sun, some early fog patches.
Headline for Snowdonia National Park
Dry, hills generally clear, sunshine.
How windy? (On the summits)
Northerly 10 to locally 15mph.
Effect of the wind on you?
Small
How Wet?
No rain
Cloud on the hills?
Little if any
Most cloud confined above higher tops. Some early fog banks in valleys.
Chance of cloud free summits?
90%
Sunshine and air clarity?
Sunshine and a little fair-weather cloud forming. Mostly excellent visibility; early low level fog.
How Cold? (at 900m)
8C
Freezing Level
Above the summits.
Viewing Forecast For
Snowdonia National Park
Tuesday 21st September 2021
Last updated
Sun 19th Sep 21 at
3:49PM
How windy? (On the summits)
West becoming southwesterly, 10 to 15mph, may reach 20mph later.
Effect of the wind on you?
Mostly small
How Wet?
Rain unlikely
Rare if any pockets of fine drizzle if around low cloud in west.
Cloud on the hills?
Occasional low cloud west
Banks of low cloud may drift onto hills nearest Cardigan Bay from time to time, although many hills often clear, with higher summits probably above lower cloud.
Chance of cloud free summits?
70%
Sunshine and air clarity?
Sunshine and high level cloud. Visibility good, but a slight haze.
How Cold? (at 900m)
11C; hills warmer than valleys at first.
Freezing Level
Above the summits
Viewing Forecast For
Snowdonia National Park
Wednesday 22nd September 2021
Last updated
Sun 19th Sep 21 at
3:49PM
How windy? (On the summits)
Southwesterly, 25 to 35mph, but may approach 50mph for a few hours, particularly Snowdon range.
Effect of the wind on you?
Expect arduous walking conditions on higher mountains much of the day. Notable wind chill where exposed.
How Wet?
Risk of rain developing
Initially mainly dry, but patchy light rain likely moving onto western coastal hills. Increasing risk of steadier rain developing as a front moves in from the northwest (timing uncertain).
Cloud on the hills?
Mostly west; extensive if rain sets in.
Banks of low cloud focused on hills nearest Cardigan Bay in the morning, but well broken further inland. If rain develops, cloud will broadly lower to blanket the hills, to lower slopes in west, but mostly above 600m in east.
Chance of cloud free summits?
20% west, to 50% east.
Sunshine and air clarity?
Occasional sun, mostly east Wales. Visibility good below cloud, but west coasts may become misty.
How Cold? (at 900m)
8 to 11C, lowest if in cloud.
Freezing Level
Above the summits
Planning Outlook
High pressure will drift southwards and southwesterly winds will strengthen across Britain in the first half of the week, soonest across Scotland. Staying windy through into next weekend, gales or sometimes severe gales on higher mountains, particularly Scotland. Rain will become frequent in western Scotland as fronts come in from the Atlantic. Spells of rain elsewhere - less wet for Wales and southern Pennines, although a risk of heavier rain moving further south by the weekend. Temperatures will vary through the next 10 days, sometimes fairly warm and humid, but chiller air spreading from the northwest at times - Scottish high tops occasionally near freezing point.