Mountain weather
Eryri / Snowdonia
Confidence
High for overall evolution but lower for details of low cloud and location of heaviest rain and showers throughout.
-
This eveningSunrise:Sunset:
-
Mon 14 SepSunrise:Sunset:
-
Tue 15 SepSunrise:Sunset:
-
Further outlook
This evening forecast
Turning cloudier through Sunday with extensive low cloud and hill fog as well as areas of patchy rain and drizzle, pushing in from the southwest.
Mountain weather hazards
Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.
Poor Visibility
Heavy Persistent Rain
Mountain weather forecast
A cloudy day ahead with patchy rain and showers.
|
Time
|
Time |
00:00
|
03:00
|
06:00
|
09:00
|
12:00
|
15:00
|
18:00
|
21:00
|
|---|---|---|---|---|---|---|---|---|---|
|
Weather
(at 800m)
|
Weather symbols | ||||||||
|
Chance of
precipitation (at 800m)
|
Chance of precipitation |
20%
|
20%
|
60%
|
20%
|
10%
|
10%
|
10%
|
40%
|
Wind direction and speed
|
Time
|
Time |
00:00
|
03:00
|
06:00
|
09:00
|
12:00
|
15:00
|
18:00
|
21:00
|
|---|---|---|---|---|---|---|---|---|---|
|
900m
|
900m | SW 36mph knots
SW
36mph |
W 29mph knots
W
29mph |
W 19mph knots
W
19mph |
W 19mph knots
W
19mph |
W 20mph knots
W
20mph |
W 19mph knots
W
19mph |
W 17mph knots
W
17mph |
W 18mph knots
W
18mph |
|
600m
|
600m | SW 25mph knots
SW
25mph |
W 21mph knots
W
21mph |
W 13mph knots
W
13mph |
W 15mph knots
W
15mph |
W 16mph knots
W
16mph |
W 15mph knots
W
15mph |
W 12mph knots
W
12mph |
W 13mph knots
W
13mph |
|
300m
|
300m | SW 18mph knots
SW
18mph |
W 15mph knots
W
15mph |
W 8mph knots
W
8mph |
W 12mph knots
W
12mph |
W 13mph knots
W
13mph |
W 13mph knots
W
13mph |
W 10mph knots
W
10mph |
W 11mph knots
W
11mph |
|
Valley
|
Valley | SW 16mph knots
SW
16mph |
W 13mph knots
W
13mph |
W 8mph knots
W
8mph |
W 12mph knots
W
12mph |
W 14mph knots
W
14mph |
W 13mph knots
W
13mph |
W 11mph knots
W
11mph |
W 11mph knots
W
11mph |
Wind gust
|
Time
|
Time |
00:00
|
03:00
|
06:00
|
09:00
|
12:00
|
15:00
|
18:00
|
21:00
|
|---|---|---|---|---|---|---|---|---|---|
|
900m
|
900m | 47mph | 38mph | 26mph | 29mph | 30mph | 30mph | 25mph | 27mph |
|
600m
|
600m | 36mph | 29mph | 19mph | 24mph | 26mph | 26mph | 20mph | 22mph |
|
300m
|
300m | 32mph | 27mph | 17mph | 22mph | 24mph | 24mph | 18mph | 20mph |
|
Valley
|
Valley | 29mph | 24mph | 16mph | 21mph | 24mph | 24mph | 19mph | 20mph |
|
Time
|
Time |
00:00
|
03:00
|
06:00
|
09:00
|
12:00
|
15:00
|
18:00
|
21:00
|
|---|---|---|---|---|---|---|---|---|---|
|
900m
|
900m | 12 degrees Celsius 12°C | 11 degrees Celsius 11°C | 9 degrees Celsius 9°C | 9 degrees Celsius 9°C | 8 degrees Celsius 8°C | 9 degrees Celsius 9°C | 8 degrees Celsius 8°C | 7 degrees Celsius 7°C |
|
600m
|
600m | 14 degrees Celsius 14°C | 13 degrees Celsius 13°C | 11 degrees Celsius 11°C | 11 degrees Celsius 11°C | 11 degrees Celsius 11°C | 11 degrees Celsius 11°C | 10 degrees Celsius 10°C | 9 degrees Celsius 9°C |
|
300m
|
300m | 16 degrees Celsius 16°C | 14 degrees Celsius 14°C | 13 degrees Celsius 13°C | 13 degrees Celsius 13°C | 13 degrees Celsius 13°C | 14 degrees Celsius 14°C | 12 degrees Celsius 12°C | 11 degrees Celsius 11°C |
|
Valley
|
Valley | 17 degrees Celsius 17°C | 16 degrees Celsius 16°C | 14 degrees Celsius 14°C | 15 degrees Celsius 15°C | 15 degrees Celsius 15°C | 15 degrees Celsius 15°C | 14 degrees Celsius 14°C | 13 degrees Celsius 13°C |
| Freezing Level | Freezing Level |
3100m
|
2900m
|
2200m
|
2100m
|
1900m
|
2000m
|
2100m
|
2100m
|
|
Time
|
Time |
00:00
|
03:00
|
06:00
|
09:00
|
12:00
|
15:00
|
18:00
|
21:00
|
|---|---|---|---|---|---|---|---|---|---|
|
900m
|
900m | 7 degrees Celsius 7°C | 6 degrees Celsius 6°C | 5 degrees Celsius 5°C | 5 degrees Celsius 5°C | 4 degrees Celsius 4°C | 5 degrees Celsius 5°C | 4 degrees Celsius 4°C | 3 degrees Celsius 3°C |
|
600m
|
600m | 10 degrees Celsius 10°C | 9 degrees Celsius 9°C | 8 degrees Celsius 8°C | 8 degrees Celsius 8°C | 8 degrees Celsius 8°C | 8 degrees Celsius 8°C | 8 degrees Celsius 8°C | 6 degrees Celsius 6°C |
|
300m
|
300m | 13 degrees Celsius 13°C | 12 degrees Celsius 12°C | 12 degrees Celsius 12°C | 11 degrees Celsius 11°C | 11 degrees Celsius 11°C | 11 degrees Celsius 11°C | 11 degrees Celsius 11°C | 9 degrees Celsius 9°C |
|
Valley
|
Valley | 15 degrees Celsius 15°C | 14 degrees Celsius 14°C | 13 degrees Celsius 13°C | 13 degrees Celsius 13°C | 13 degrees Celsius 13°C | 13 degrees Celsius 13°C | 12 degrees Celsius 12°C | 11 degrees Celsius 11°C |
| Freezing Level | Freezing Level |
3100m
|
2900m
|
2200m
|
2100m
|
1900m
|
2000m
|
2100m
|
2100m
|
Additional weather information
Meteorologist's view
Low cloud and poor visibilities will make navigation challenging, combined with wet surfaces and rain, suitable clothing is a necessity.
Weather
A cloudy day ahead with outbreaks of light and patchy rain possible throughout the day, some of this rain may turn heavy around dawn. Cloud may lift somewhat through the afternoon to allow for the odd brighter spell. Moderate southwesterly wind.
Chance of cloud-free hill tops
<10% through the morning rising to 40% through the afternoon before dropping to <10% once again.
Low cloud and visibility
Extensive low cloud initially between 300-400m. Through the morning cloud bases lifting to 600-800m, with some patchier cloud at 500m. Cloud bases then gradually lowering again into the evening. Generally poor to very poor visibility in rain and low cloud, but good outside of low cloud.
Ground conditions
No recent ground conditions report available.
Mountain weather information
Weather
Overnight rain and cloud gradually moving southeast, likely clearing the park before dawn. Beyond this a drier and brighter day with the potential for some isolated showers through the afternoon.
Chance of cloud-free hill tops
20% initially but quickly rising to 90% by dawn as cloud clears south.
Maximum wind speed expected
Westerly 25-30 mph.
Temperature
- At 800m plus 4 Celsius rising to plus 7 Celsius.
- Valley plus 11 Celsius rising to plus 16 Celsius.
- Freezing level Above summits.
Low cloud and visibility
Cloud bases initially between 400-500m, but soon after dawn all cloud bases are expected to lift above summits. Good visibilities initially but poor or very poor in low cloud and hill fog. Visibilities becoming very good or excellent through the morning with views of distant peaks possible, potentially dropping to moderate in any passing showers.
Ground conditions
No recent ground conditions report available.
Mountain weather information
Wed 16 Sep
Largely dry with sunny intervals and some scattered showers. Moderate to fresh westerly.
Thu 17 Sep
Overnight rain quickly clearing to leave a drier and brighter day with scattered showers, these potentially heavy at times. Fresh to occasionally strong westerly winds.
Fri 18 Sep
A generally dry day with patchy cloud and sunny spells. Rain and cloud likely arriving from the west later.
Summit specific forecast
The Eryri (Snowdonia) mountains are made up of 90 mountain peaks including the tallest mountain in Wales, Yr Wyddfa (Snowdon), standing at 1,085 metres.