Mountain weather

Eryri / Snowdonia

Eryri / Snowdonia Mountain weather forecast table

Confidence

High confidence for unsettled conditions to dominate but lower confidence for frontal zone positions and associated cloud and rainfall detail.

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 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 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.

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

Wet for much of the day, although perhaps a brief drier interlude in the afternoon. Strong winds at summit level.

Time 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
Heavy rain Drizzle Cloudy Cloudy Cloudy Cloudy
Chance of precipitation
(at 800m)
>95% >95% 30% 20% 10% 20%

Wind direction and speed (mph)
Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m SW
50
SW
43
SW
35
SW
32
SW
32
SW
31
600m SW
34
SW
30
SW
27
SW
26
SW
24
SW
22
300m SW
20
SW
19
SW
17
SW
16
SW
14
SW
13
Valley SW
20
SW
19
SW
16
SW
16
SW
14
SW
13
Wind gust (mph)
Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m 59 52 44 42 41 39
600m 42 38 36 35 32 29
300m 35 33 30 30 27 24
Valley 35 32 29 29 26 24

Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m
11°
12°
11°
10°
600m
13°
14°
13°
12°
11°
11°
300m
15°
15°
16°
15°
13°
13°
Valley
16°
16°
17°
16°
15°
14°
Freezing Level
3,900m
2,900m
2,600m
2,400m
2,500m
2,500m

Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
900m
600m
300m
11°
12°
13°
12°
11°
10°
Valley
12°
13°
15°
14°
12°
12°

Additional weather information

Meteorologist's view

Wet conditions in the morning, slippery underfoot so waterproofs will be needed. Winds at summit level could be particularly strong around exposed peaks and ridges.

Weather

Heavy rain overnight and early on Wednesday, easing through the morning to become generally dry by the afternoon. A small chance of outbreaks of light rain and drizzle through the day, especially on western slopes. Perhaps some drier interludes in the afternoon in eastern shelter but this is low confidence.

Chance of cloud-free hill tops

Near zero for much of the day.

Low cloud and visibility

Extensive bases above 400m, perhaps lower at times on western slopes. Perhaps a few breaks developing for a time in eastern shelter in the afternoon, but this is low confidence. Visibility generally moderate to poor in outbreaks of rain and very poor in summit cloud.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

Most likely staying wet with further outbreaks of rain, perhaps heavy at times, especially across western slopes. Becoming drier in the afternoon, though there will be plenty of low cloud around. Windy across the summits.

Chance of cloud-free hill tops

Near zero for much of the day.

Maximum wind speed expected

South-southwest 40-50mph, gust 50-60mph.

Temperature

  • At 800m Plus 12 Celsius
  • Valley Plus 13 Celsius rising to 18 Celsius.
  • Freezing level Well above summits.

Low cloud and visibility

Extensive bases above 400-600m, with visibility generally moderate to poor in outbreaks of rain and very poor in summit cloud.

Mountain weather information

Fri 19 Sep

Sunrise:
Sunset:

The band of cloud and rain should clear south for a time before returning north again later. Strong southwest winds.

Sat 20 Sep

Sunrise:
Sunset:

Confidence becomes low for detail, but currently there is a likelihood of a spell of persistent, heavy rain, perhaps with strong to gale force northerly winds developing across summits.

Sun 21 Sep

Sunrise:
Sunset:

Probably turning drier and brighter from the north with improving cloud bases and visibility. Strong to gale force northerly winds possible across summits.

Updated at:

Summit specific forecast

Mountain summit forecast map

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