Mountain weather

Eryri / Snowdonia

Yellow warning

Yellow weather warning in force for Eryri / Snowdonia

Eryri / Snowdonia Mountain weather forecast table

Confidence

High for very windy, cold and showery conditions on Sunday then a transition to a much milder southwesterly early next week.

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 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 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 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

Very windy and cold with frequent wintry showers.

06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
Light snow shower (night) Light snow shower (day) Cloudy Sunny intervals Partly cloudy (night) Partly cloudy (night)
Chance of precipitation
(at 800m)
80% 80% 30% 10% <5% <5%

Wind direction and speed (mph)
Altitude above mean sea level
06:00 09:00 12:00 15:00 18:00 21:00
900m W
52
NW
50
NW
50
NW
48
NW
44
NW
40
600m W
38
NW
35
NW
37
NW
35
NW
32
NW
29
300m W
27
NW
24
NW
27
NW
25
NW
22
NW
20
Valley W
27
NW
25
NW
28
NW
26
NW
23
NW
22
Wind gust (mph)
Altitude above mean sea level
06:00 09:00 12:00 15:00 18:00 21:00
900m 61 59 64 61 56 51
600m 46 44 50 47 43 40
300m 42 40 46 44 39 35
Valley 42 40 47 45 41 37

Altitude above mean sea level
06:00 09:00 12:00 15:00 18:00 21:00
900m
-3°
-3°
-2°
-1°
-1°
-2°
600m
-1°
-1°
300m
Valley
Freezing Level
400m
400m
600m
600m
600m
600m

Altitude above mean sea level
06:00 09:00 12:00 15:00 18:00 21:00
900m
-14°
-14°
-12°
-11°
-11°
-11°
600m
-10°
-10°
-8°
-6°
-6°
-7°
300m
-6°
-6°
-3°
-2°
-2°
-2°
Valley
-4°
-4°
-1°

Additional weather information

Meteorologist's view

Severe gales, with storm force winds at times on ridges and summits with gusts of 70 to 80mph. Walking severely hampered, almost impossible at times. Bitterly cold on the tops.

Weather

Bright spells and showers, falling as snow to 300m in the morning with a small chance of hail and thunder. The showers will become less frequent through the afternoon, falling as snow above 500m. Very strong and gusty winds with a severe wind chill.

Chance of cloud-free hill tops

30% overnight and morning improving to 60% in the afternoon.

Low cloud and visibility

Frequent cloud above 400m overnight and morning, becoming patchy above 600m in the afternoon. Mainly good visibility between showers but poor in showers, down to a few hundred metres at times in snow with blizzard conditions possible on the tops.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

Clear spells overnight with scattered showers, wintry above 400m, then a dry and sunny start with lighter winds. Turning cloudy from midday with outbreaks of rain and drizzle arriving in the afternoon. Turning milder.

Chance of cloud-free hill tops

90% in morning, reducing to 10% in afternoon.

Maximum wind speed expected

Northwest 30 to 40mph gusts 55mph easing to 15 to 20mph, becoming Southwest in afternoon.

Temperature

  • At 800m Minus 1C rising to 3C in afternoon.
  • Valley Plus 1 to 3C rising to 8C.
  • Freezing level 500m, rising above summits in afternoon.

Low cloud and visibility

Excellent visibility in morning then becoming poor in afternoon rain. Cloud and fog becoming extensive above 400m in afternoon, down to low slopes in south and west.

Mountain weather information

Tue 24 Dec

Sunrise:
Sunset:

Extensive low cloud and outbreaks of rain or drizzle. Fresh southwest winds on the tops. Mild with freezing level well above the summits.

Wed 25 Dec

Sunrise:
Sunset:

Cloudy but mainly dry with the odd spot of rain. Fresh southwest winds on the tops. Mild.

Thu 26 Dec

Sunrise:
Sunset:

Continuing mostly cloudy and dry. Light southwest winds. Mild.

Updated at:

Summit specific forecast

Mountain summit forecast map

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