Mountain weather

Eryri / Snowdonia

Eryri / Snowdonia Mountain weather forecast table

Confidence

High for gradual warmer and more humid trend, moderate for cloud and rainfall detail on Friday.

Sunrise:
Sunset:
Mountain hazards

Mountain weather hazards

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

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.

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.

Mountain weather forecast

Fine but mostly cloudy during the morning. Spells of rain making very gradual erratic inroads from west later.

06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
Overcast Sunny intervals Sunny intervals Cloudy Light rain Heavy rain
Chance of precipitation
(at 800m)
10% 10% 20% 20% 40% 60%

Wind direction and speed (mph)
Altitude above mean sea level
06:00 09:00 12:00 15:00 18:00 21:00
900m SW
25
SW
26
SW
26
SW
28
SW
28
S
22
600m SW
22
SW
24
SW
25
SW
25
SW
21
S
15
300m S
14
SW
18
SW
18
SW
19
S
15
S
10
Valley S
14
S
16
SW
17
S
18
S
14
S
10
Wind gust (mph)
Altitude above mean sea level
06:00 09:00 12:00 15:00 18:00 21:00
900m 31 34 35 38 36 28
600m 30 32 35 35 29 21
300m 26 29 31 32 26 19
Valley 24 27 30 30 24 19

Altitude above mean sea level
06:00 09:00 12:00 15:00 18:00 21:00
900m
600m
10°
10°
10°
10°
300m
11°
12°
12°
13°
12°
12°
Valley
13°
14°
14°
15°
13°
13°
Freezing Level
2,900m
2,900m
2,700m
1,900m
2,600m
2,500m

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

Additional weather information

Meteorologist's view

Conditions generally deteriorating through the day, with this trend accelerating late on. Care advised with late descents.

Weather

Rather cloudy, with some limited bright or sunny intervals for a time, but gradually followed by further thickening cloud from the west. Some showery rain is possible through the afternoon, mostly light at first, but eventually becoming heavier and persistent into the evening as a band of rain stalls over the area.

Chance of cloud-free hill tops

40%, improving to 80% during the day, reducing to 20% later in the day.

Low cloud and visibility

Cloud obscuring tops above 500m at times through the morning but lifting to around 800m through the morning and early afternoon. Cloud then thickening and lowering to affect most ground above 400 metres by evening. Visibility initially good, but falling to become poor in rain and drizzle with time.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

Any rain becoming lighter and more intermittent during the early hours, and clearing eastwards around dawn. A largely fine day with some sunny spells follows, bringing a high UV. Cloud increasing again from the west later in the afternoon, becoming extensive down to valley floors on windward ground by dusk, with some light rain or drizzle likely.

Chance of cloud-free hill tops

40% at first, rising to 90%. Falling in the afternoon to near nil by the evening.

Maximum wind speed expected

Southwesterly 15-20mph gusting 30mph.

Temperature

  • At 800m Plus 8 Celsius
  • Valley Plus 8 Celsius becoming Plus 21 Celsius
  • Freezing level Well above the summits

Low cloud and visibility

Broken cloud obscuring tops and routes above 600 metres during the hours and again late in the afternoon, before potentially falling to 300 metres during the evening. Visibility mostly good but deteriorating to moderate at times, especially in ay rain or drizzle that occurs.

Mountain weather information

Sun 23 Jun

Sunrise:
Sunset:

Probably rather cloudy and close, with the odd spot of rain tending to fade later. Light winds, perhaps mainly from west.

Mon 24 Jun

Sunrise:
Sunset:

Becoming increasingly warm and humid in a very different feel to the first half of June, with UV indices near an annual peak. Fine but potentially arduous going in the heat of the day. Light winds.

Tue 25 Jun

Sunrise:
Sunset:

Fine and very warm with strong sunshine. Outside chance of a shower. Light to moderate southeasterly winds.

Updated at:

Summit specific forecast

Mountain summit forecast map

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