Mountain weather

Mountain weather

Eryri / Snowdonia

Confidence

High for the overall theme. Lower confidence for any heavy downpours on Friday.

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.

Mountain weather forecast

Often cloudy with showers by the afternoon.

Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
Weather
(at 800m)
Weather symbols Light rain Cloudy Light rain showers Heavy rain showers Heavy rain showers Light rain showers
Chance of
precipitation
(at 800m)
Chance of precipitation
30%
20%
40%
60%
60%
30%

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 S 16mph knots
S
16mph
SE 8mph knots
SE
8mph
E 8mph knots
E
8mph
NE 6mph knots
NE
6mph
NE 10mph knots
NE
10mph
NE 14mph knots
NE
14mph
600m
600m S 10mph knots
S
10mph
S 7mph knots
S
7mph
NE 7mph knots
NE
7mph
NE 7mph knots
NE
7mph
N 6mph knots
N
6mph
E 6mph knots
E
6mph
300m
300m SE 5mph knots
SE
5mph
S 4mph knots
S
4mph
NE 7mph knots
NE
7mph
NE 6mph knots
NE
6mph
N 6mph knots
N
6mph
N 3mph knots
N
3mph
Valley
Valley SE 5mph knots
SE
5mph
S 4mph knots
S
4mph
NE 7mph knots
NE
7mph
N 6mph knots
N
6mph
N 6mph knots
N
6mph
N 2mph knots
N
2mph

Wind gust

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 19mph 11mph 11mph 9mph 13mph 21mph
600m
600m 14mph 9mph 10mph 10mph 9mph 12mph
300m
300m 11mph 5mph 10mph 9mph 10mph 8mph
Valley
Valley 11mph 5mph 10mph 9mph 10mph 7mph

Altitude above mean sea level
Time
Time
06:00
09:00
12:00
15:00
18:00
21:00
900m
900m 0 degrees Celsius 2 degrees Celsius 4 degrees Celsius 4 degrees Celsius 3 degrees Celsius 1 degrees Celsius
600m
600m 4 degrees Celsius 6 degrees Celsius 7 degrees Celsius 6 degrees Celsius 7 degrees Celsius 6 degrees Celsius
300m
300m 8 degrees Celsius 10 degrees Celsius 10 degrees Celsius 10 degrees Celsius 9 degrees Celsius 9 degrees Celsius
Valley
Valley 9 degrees Celsius 11 degrees Celsius 11 degrees Celsius 11 degrees Celsius 10 degrees Celsius 10 degrees Celsius
Freezing Level Freezing Level
1400m
1400m
1600m
1700m
1700m
1700m

Additional weather information

Meteorologist's view

Poor conditions to start with good navigational skills required. UV still strong despite cloud cover so sun protection advised as well as a waterproof if caught in a heavy downpour.

Weather

Cloudy through the early hours with outbreaks of rain. Some sunny breaks into the afternoon but also with the risk of showers, these heavy at times later in the day with the low chance of turning thundery. These fading by the evening with cloud lowering by the evening.

Chance of cloud-free hill tops

50% rising to 70% by mid-afternoon.

Low cloud and visibility

Patchy cloud around 400-500 m initially, then gradually lifting mostly above summits by midday but shrouding highest peaks. Low cloud moving in by the evening down to 600-700 m. Poor visibility first thing in rain then very good by the afternoon. Dropping in any sharp showers.

Ground conditions

Please see - https://yrwyddfa.live/

Summit specific forecast