Mountain weather

Eryri / Snowdonia

Eryri / Snowdonia Mountain weather forecast table

Confidence

High overall. Main uncertainties are the location of the strongest gusts during Saturday evening. Moderate for frontal timings on Wednesday and Thursday.

Sunrise:
Sunset:
Mountain hazards

Mountain weather hazards

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

hazard 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.
hazard 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.

hazard 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.

hazard Blizzards
Blizzards and whiteouts present challenging and serious conditions due to a combination of falling or blowing snow, strong winds and cold temperatures. They can be highly disorientating, often resulting in near-zero visibility with limited or no visual references and no distinction between ground and sky. Cliff edges and cornices may not be apparent, even close up. These conditions require very good navigational skills.
hazard Storm Force Winds
Storm force winds (gusts over 70mph) make walking very strenuous with any mobility virtually impossible over exposed ground. Where these conditions occur there is a high risk of being blown over and even standing may be impossible at times with a risk of being blown off one’s feet. Basic tasks such as using a map, eating, putting on extra clothing or communication become extremely difficult away from any shelter.
hazard 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.
hazard 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.

Mountain weather forecast

Sunshine and showers. Mostly dry by the afternoon. Often windy. Easing later.

Time 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
Heavy snow Light snow shower (day) Light snow Light snow Cloudy Clear night
Chance of precipitation
(at 800m)
60% 30% 20% 20% 10% 10%

Wind direction and speed (mph)
Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m W
36
W
34
W
34
W
29
W
24
W
16
600m W
23
W
25
W
25
W
24
W
16
SW
10
300m W
15
W
18
W
19
W
16
W
10
SW
5
Valley W
15
W
18
W
19
W
16
W
10
SW
5
Wind gust (mph)
Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m 43 42 43 37 30 20
600m 29 32 34 31 21 13
300m 26 29 31 27 19 9
Valley 26 29 31 27 18 9

Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m
-2°
-2°
-1°
-1°
-1°
600m
300m
Valley
Freezing Level
600m
500m
400m
600m
600m
600m

Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m
-11°
-11°
-10°
-9°
-8°
-6°
600m
-7°
-6°
-5°
-4°
-3°
-2°
300m
-2°
-2°
Valley

Additional weather information

Meteorologist's view

Winds less strong on Sunday though still often windy across summits.

Weather

A much colder day ahead but with drier and brighter conditions. Patchy cloud likely throughout the day, with the risk of showers remaining, mainly through the morning. Remaining windy with gales likely on summits.

Chance of cloud-free hill tops

60% gradually rising to 80% from afternoon onward.

Low cloud and visibility

Cloud bases generally above summits with patchy cloud at 700-1000m covering summits at times through the morning. Very good visibility in general though may become poor in showers and very poor in low cloud or hill fog.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

A cold start with patchy frost in places. Then a settled day ahead and remaining dry. Sunny spells likely though a build of high cloud at times will create hazier spells of sunshine. Light winds though perhaps a moderate breeze across the highest peaks later.

Chance of cloud-free hill tops

90%

Maximum wind speed expected

15-20 mph

Temperature

  • At 800m Zero Celsius rising to plus 2 Celsius.
  • Valley Plus 4 Celsius rising to plus 14 Celsius.
  • Freezing level At summits.

Low cloud and visibility

A small chance of some isolated mist or fog patches to start then very little to no low cloud during the day and good to excellent visibility.

Mountain weather information

Tue 7 Apr

Sunrise:
Sunset:

Dry with plenty of sunshine to start the day. A build of high cloud may create hazier spells of sunshine. Fresh to strong southeasterly winds.

Wed 8 Apr

Sunrise:
Sunset:

A cloudier day ahead with the potential for some showery outbreaks. Moderate to fresh southerly winds.

Thu 9 Apr

Sunrise:
Sunset:

Sunshine and showers. Strong westerly winds.

Updated at:

Summit specific forecast

Mountain summit forecast map

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