Snowdonia National Park Forecast

Viewing Weather Forecast for Saturday 27th May 2017

Also includes higher summits south to Plynlimon.

Today | Sunday | Monday

Forecast last updated on Friday 26th May 2017 at 4:27pm

Summary for all mountain areas

An active frontal zone will spread north-eastwards through the day, triggering thunderstorms - torrential rain, hail and frequent lightning, plus sudden gusty winds. The Scottish Highlands will generally deteriorate by afternoon onward. Meanwhile, Wales will generally improve.

Headline for Snowdonia National Park

Thunderstorms, likely all clearing into afternoon.

How windy? (On the summits)

South veering southwest, later westerly; 20 to 30mph, strongest morning, then easing to 15-20mph afternoon, or less by evening.

Effect of wind on you?

Frequent buffeting on hills for several hours, sudden very strong gusts to low levels around thunderstorms; easing later.

How Wet?

Thunderstorms, clearing

Heavy rain and thunderstorms from before dawn will likely continue in the morning, giving local torrential bursts. Rain will mostly all clear by early afternoon, leaving just isolated showers.

Cloud on the hills?

Widespread in rain, lifting

Banks of low cloud covering the hills during rain, in places from forest canopies up. Tending to lift and break up, and eastern summits should slowly clear.

Chance of cloud free summits?

20% morning; 50% afternoon.

Sunshine and air clarity?

Widely cloudy morning, but sunshine breaking through increasingly by afternoon. Visibility reduced significantly by rain, but improving through day.

How Cold? (at 900m)

Starting very warm at 15C or above, but later dropping to 10C from west.

Freezing Level

Above the summits

Planning Outlook

All mountain areas of Britain from Sunday 28th May 2017

Following Saturday's thundery breakdown, most areas will be dry into Sunday, and cooler than previous days. On Monday, there is a risk of further thundery rain extending from the south, although detail is uncertain. For the rest of the week, high pressure will be to the south & south-east, allowing some dry and bright days, but fronts will try and encroach from the Atlantic, bringing occasional rain to mainly western Scotland. A generally more unsettled pattern is likely to develop as the week progresses, with rain becoming more frequent, and winds strengthening at times.