Mountain weather

Mountain weather

Eryri / Snowdonia

Confidence

High confidence in the overall weather but precise shower detail and timing remains lower confidence.

Mountain hazards

Mountain weather hazards

Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.

Severe Chill Effect
Wind significantly lowers the ‘feels-like’ temperature relative to the actual temperature, with even moderate winds significantly adding to the chilling effect. Strong winds can result in a severe and debilitating wind chill many degrees below the actual temperature. This effect will be enhanced in rain or wet snow. Without protection, prolonged exposure could result in frost nip or frostbite on exposed parts of the body and/or hypothermia.
Heavy Persistent Rain
Heavy and persistent rain can lead to drenched clothing and footwear with waterproofs often becoming soaked through, especially if accompanied by strong winds. This can lead to significant loss of body heat and an increased likelihood of hypothermia. Terrain may turn increasingly boggy underfoot while streams can flood and become impassable. There may also be a risk of flooding in valleys or glens. If there is snow cover, a heightened avalanche hazard is possible and avalanche reports should be consulted where available.
Strong Sunlight
Harmful UV levels from sunlight increase with altitude giving a greater risk of sunburn and eye damage, even on some overcast days. On breezy days, the cooling effect of wind on exposed skin may disguise any feeling of sunburn until it is too late. If there is snow cover, glare increases the effect of UV rays especially on the eyes. It is advisable to wear sun block, protective clothing such as a long-sleeved top and hat and have good quality eye protection.

Gales
Gale force winds (gusts over 50mph) make walking difficult and strenuous with a potential to be blown over by gusts. There is often a marked increase in winds through cols or on exposed ridges and summits. Distances can take longer to cover and compass bearings become harder to follow accurately.
Poor Visibility
Poor visibility presents challenging route finding conditions. Visibility could be significantly less than 50 metres in all directions with few or no visual references, especially on featureless moors or plateaux. Distances become hard to judge and cliff or cornice edges can be difficult to recognise. These conditions require good navigational skills. There is a risk of white-out conditions when mist or fog is combined with extensive snow cover.
Thunderstorms
Lightning is a significant mountain hazard which can result in serious injury or death. Mountain terrain often leaves one highly exposed to lightning strikes. Hail may give unpleasant conditions with torrential rain and localised flash flooding also possible, mainly in Summer months.

Mountain weather forecast

Heavy blustery showers and feeling cold despite some brighter spells.

Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
Weather symbols Sleet showers Sleet showers Heavy rain showers Heavy rain showers Sleet showers Sleet showers (night)
Chance of
precipitation
(at 800m)
Chance of precipitation
90%
90%
90%
90%
80%
80%

Wind direction and speed

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m W 37mph knots
W
37mph
NW 35mph knots
NW
35mph
NW 30mph knots
NW
30mph
NW 30mph knots
NW
30mph
NW 31mph knots
NW
31mph
NW 32mph knots
NW
32mph
600m
600m W 26mph knots
W
26mph
NW 25mph knots
NW
25mph
NW 23mph knots
NW
23mph
NW 22mph knots
NW
22mph
NW 21mph knots
NW
21mph
NW 19mph knots
NW
19mph
300m
300m W 18mph knots
W
18mph
NW 18mph knots
NW
18mph
NW 17mph knots
NW
17mph
NW 16mph knots
NW
16mph
NW 15mph knots
NW
15mph
NW 13mph knots
NW
13mph
Valley
Valley W 18mph knots
W
18mph
NW 18mph knots
NW
18mph
NW 17mph knots
NW
17mph
NW 16mph knots
NW
16mph
NW 15mph knots
NW
15mph
NW 13mph knots
NW
13mph

Wind gust

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 44mph 42mph 39mph 39mph 39mph 40mph
600m
600m 32mph 32mph 31mph 31mph 28mph 26mph
300m
300m 29mph 29mph 29mph 27mph 26mph 24mph
Valley
Valley 29mph 29mph 29mph 27mph 27mph 24mph

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m -8 degrees Celsius -7 degrees Celsius -5 degrees Celsius -4 degrees Celsius -5 degrees Celsius -6 degrees Celsius
600m
600m -4 degrees Celsius -3 degrees Celsius -1 degrees Celsius 0 degrees Celsius -1 degrees Celsius -2 degrees Celsius
300m
300m 1 degrees Celsius 2 degrees Celsius 4 degrees Celsius 4 degrees Celsius 3 degrees Celsius 2 degrees Celsius
Valley
Valley 3 degrees Celsius 4 degrees Celsius 6 degrees Celsius 6 degrees Celsius 5 degrees Celsius 4 degrees Celsius
Freezing Level Freezing Level
900m
1000m
1100m
1100m
1100m
1100m

Additional weather information

Meteorologist's view

Frequent and locally heavy showers will bring a very changeable day. Care needed if heading into the hills with temperatures feeling cold at height, gusty winds and a risk of thunder. UV levels also remaining high in any brighter spells.

Weather

A mixture of sunshine and blustery showers likely through the day with fresh north-westerly winds. Showers heavy at times, with a risk of hail and thunder, and a lower freezing level seeing rain turn to sleet over the highest tops through the day.

Chance of cloud-free hill tops

60%.

Low cloud and visibility

Cloud bases mostly around 600-800m throughout, enough to shield summits at times. Visibility will generally be very good, although falling rapidly within any heavy showers to become moderate to poor, and locally very poor in any cloud and sleet at height.

Ground conditions

Please see - https://yrwyddfa.live/

Summit specific forecast