Mountain weather

Mountain weather

Eryri / Snowdonia

Confidence

High for a day of heavy showers and Thursday, and moderate for these to occasionally turn thundery with hail. Confidence in the location and persistence of any heavier rain and subsequently any low cloud remain low however. Also high confidence for showers to be less frequent on Friday, with a general drier and more settled feel to conditions into the weekend. High confidence for staying rather cool.

Mountain hazards

Mountain weather hazards

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

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.
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.
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.

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

Sunshine and showers.

Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
Weather symbols Heavy Rain Thunderstorm Heavy rain showers Sunny intervals Sunny intervals Partly cloudy (night)
Chance of
precipitation
(at 800m)
Chance of precipitation
70%
70%
70%
70%
70%
40%

Wind direction and speed

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m NW 14mph knots
NW
14mph
NW 14mph knots
NW
14mph
N 21mph knots
N
21mph
N 23mph knots
N
23mph
N 20mph knots
N
20mph
N 18mph knots
N
18mph
600m
600m NW 9mph knots
NW
9mph
NW 12mph knots
NW
12mph
N 16mph knots
N
16mph
N 18mph knots
N
18mph
N 14mph knots
N
14mph
NW 9mph knots
NW
9mph
300m
300m NW 6mph knots
NW
6mph
NW 8mph knots
NW
8mph
N 12mph knots
N
12mph
N 13mph knots
N
13mph
N 11mph knots
N
11mph
NW 6mph knots
NW
6mph
Valley
Valley NW 6mph knots
NW
6mph
NW 8mph knots
NW
8mph
N 12mph knots
N
12mph
N 13mph knots
N
13mph
N 11mph knots
N
11mph
NW 6mph knots
NW
6mph

Wind gust

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 17mph 17mph 27mph 29mph 26mph 23mph
600m
600m 11mph 15mph 22mph 24mph 19mph 13mph
300m
300m 10mph 13mph 20mph 22mph 18mph 13mph
Valley
Valley 10mph 13mph 21mph 22mph 18mph 13mph

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 6 degrees Celsius 6 degrees Celsius 5 degrees Celsius 4 degrees Celsius 4 degrees Celsius 3 degrees Celsius
600m
600m 9 degrees Celsius 9 degrees Celsius 8 degrees Celsius 8 degrees Celsius 8 degrees Celsius 8 degrees Celsius
300m
300m 11 degrees Celsius 11 degrees Celsius 11 degrees Celsius 11 degrees Celsius 12 degrees Celsius 11 degrees Celsius
Valley
Valley 12 degrees Celsius 13 degrees Celsius 12 degrees Celsius 13 degrees Celsius 13 degrees Celsius 13 degrees Celsius
Freezing Level Freezing Level
2200m
2200m
2200m
2100m
2000m
1900m

Additional weather information

Meteorologist's view

A poor start to the day with difficult navigation, and the potential to be caught in a thunderstorm. Improving during the afternoon but a day to be prepared for most eventualities, with adequate waterproofs, layers and sunscreen as required.

Weather

Often cloudy with heavy showers likely, along with the chance of thunderstorms with hail. Perhaps some gusty winds along with the heavier showers. Brief drier interludes and glimpses of sunshine can also be expected in between showers.

Chance of cloud-free hill tops

40% rising to 80%

Low cloud and visibility

Areas of cloud will often obscure hills above 600m during the morning, with some heavier bursts of rain leading to some patches as low as 400m. Some breaks are likely, even across highest hills. This cloud then lifts into the afternoon, rising above most tops, with just the odd patch perhaps returning above 700m with the heaviest showers. Outside of cloud and showers, good to very good views are to be found but spells of moderate to poor visibility are expected during any heavier bursts.

Ground conditions

Please see - https://yrwyddfa.live/

Summit specific forecast