Mountain weather

Eryri / Snowdonia

Eryri / Snowdonia Mountain weather forecast table

Confidence

High for cold, showery, northwest flow for Saturday, then for milder westerly pattern from Sunday, but lowering for the timing detail of later poorer weather.

Sunrise:
Sunset:
Mountain hazards

Mountain weather hazards

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

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 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.

Mountain weather forecast

Turning cold with showers. Snow level lowering to 700m. Strong to gale northwest summit winds bringing severe wind chill.

Time 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
Sleet shower (night) Sleet shower (day) Sleet shower (day) Sleet Heavy snow Heavy snow
Chance of precipitation
(at 800m)
60% 60% 60% 40% 70% 70%

Wind direction and speed (mph)
Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m N
39
NW
36
NW
37
NW
32
NW
35
NW
33
600m N
25
NW
23
NW
26
NW
20
NW
23
NW
22
300m N
16
NW
16
NW
19
NW
13
NW
15
NW
14
Valley N
16
NW
17
NW
20
NW
13
NW
16
NW
15
Wind gust (mph)
Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m 46 43 45 40 43 41
600m 31 30 34 27 31 29
300m 28 28 31 21 27 25
Valley 29 28 33 22 28 26

Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m
600m
300m
Valley
Freezing Level
1,000m
900m
800m
900m
1,000m
900m

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

Additional weather information

Meteorologist's view

Severe wind chill extending to quite low levels.

Weather

Sleet showers and limited clear spells before dawn. Then sleet showers or longer spells of sleet and limited brighter spells today. These will be mostly light before turning heavier and more frequent from late afternoon and especially this evening. Snow level lowering to 600-700m from mid-afternoon. Feeling cold in strong summit winds as the freezing level lowers. Low risk of summit blizzards this evening.

Chance of cloud-free hill tops

70% by day

Low cloud and visibility

Very good becoming moderate or poor in showers, very poor in snow also within cloud with bases occasionally lowering to 600m, particularly as showers push through.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

Scattered showers and brighter spells at first, snow level 700m. Area of rain reaching from the west late morning, briefly falling as snow across highest peaks, clearing to showers during the afternoon. Fresh summit winds increasing severe gale, perhaps storm force for the afternoon, but extent of windchill lessening as the freezing level lifts.

Chance of cloud-free hill tops

70% becoming 10% late morning and 70% from late afternoon

Maximum wind speed expected

Westerly increasing mean 50mph by late afternoon with gusts reaching 60-70mph across most exposed ridges and summits.

Temperature

  • At 800m Zero Celsius increasing 6 Celsius during the afternoon
  • Valley Plus 2 Celsius increasing 12 Celsius during the afternoon
  • Freezing level 800m lifting above all summits by late morning

Low cloud and visibility

Good or very good becoming moderate or poor in rain or showers, very poor within cloud bases, which become quite extensive from 500-600m late morning and much of the afternoon and occasionally so from late afternoon in the showery flow.

Mountain weather information

Mon 27 Oct

Sunrise:
Sunset:

Scattered showers and brighter spells, but increasing chance of rain developing later in the day. Strong summit winds. Freezing level above summits.

Tue 28 Oct

Sunrise:
Sunset:

Rather cloudy with showers, perhaps merging to longer periods of rain at times. Strong summit winds. Freezing level above summits.

Wed 29 Oct

Sunrise:
Sunset:

Rather cloudy with patchy rain. Strong summit winds. Freezing level above summits.

Updated at:

Summit specific forecast

Mountain summit forecast map

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