Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for the general story of sunshine and showers, but low for the detail of the showers including thunderstorm potential on Tuesday. Confidence especially Low on Wednesday, but likely a cloudier day with either persistent rain, or a further risk of showers. Low confidence continues Thursday, as any cloud and rain from Wednesday may be slow to clear. Confidence improving for a more benign and largely fine end to the week, but still a risk of isolated showers.
Mountain weather hazards
Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.
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.
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.
Mountain weather forecast
Mostly cloudy with isolated heavy showers, perhaps thundery.
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
<05% | 20% | 40% | 30% | 30% | 10% |
Wind direction and speed (mph)
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
NE
6
|
E
4
|
NW
7
|
N
5
|
N
3
|
SW
5
|
| 600m |
E
4
|
NE
4
|
NW
6
|
N
4
|
N
3
|
SW
3
|
| 300m |
S
2
|
N
4
|
NW
6
|
NW
3
|
NW
2
|
SE
2
|
| Valley |
S
2
|
N
4
|
N
7
|
NW
3
|
W
2
|
S
2
|
Wind gust (mph)
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m | 8 | 6 | 11 | 8 | 6 | 6 |
| 600m | 5 | 7 | 10 | 7 | 5 | 4 |
| 300m | 4 | 7 | 10 | 6 | 4 | 3 |
| Valley | 3 | 8 | 12 | 6 | 4 | 3 |
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
9°
|
10°
|
11°
|
10°
|
10°
|
9°
|
| 600m |
11°
|
12°
|
13°
|
12°
|
12°
|
11°
|
| 300m |
13°
|
14°
|
16°
|
14°
|
14°
|
13°
|
| Valley |
14°
|
16°
|
16°
|
15°
|
15°
|
13°
|
| Freezing Level |
2,000m
|
2,000m
|
2,200m
|
2,200m
|
2,100m
|
2,100m
|
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
8°
|
9°
|
9°
|
8°
|
10°
|
8°
|
| 600m |
10°
|
11°
|
12°
|
11°
|
12°
|
11°
|
| 300m |
13°
|
14°
|
15°
|
14°
|
14°
|
13°
|
| Valley |
14°
|
15°
|
15°
|
15°
|
15°
|
13°
|
Additional weather information
Meteorologist's view
Sun protection and waterproof layers essential, with a chance of both warm sunny spells and a few heavy downpours. Chance of thunderstorms, so worth being aware of what to do if caught in one.
Weather
Mostly cloudy with isolated heavy showers from mid-morning, possibly thundery. Bright or sunny spells are possible, most likely in the west. Cloud increasing from the east through the afternoon, however, and likely lowering to cover some tops during the late evening
Chance of cloud-free hill tops
90%, falling to 60% during the evening
Low cloud and visibility
Cloud above summits for much of the day, perhaps the odd ragged patch above 900m during any heavy showers or thunderstorms. Areas of cloud also potentially lowering to 500m during the evening. Visibility generally good, but views becoming more limited during showers as visibility becomes poor.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Perhaps the odd mist or fog patch developing, but soon lifting. Otherwise cloud potentially thickening from the west, bringing a chance of rain or showers, perhaps turning persistent. This most likely across eastern hills. Turning breezy, especially at height
Chance of cloud-free hill tops
60% west, 30% east
Maximum wind speed expected
Northwesterly 15-20mph increasing to 25mph with 30-40mph gusts.
Temperature
- At 800m Plus 6 Celsius becoming Plus 8 Celsius.
- Valley Plus 8 Celsius becoming Plus 11 Celsius.
- Freezing level Above summits.
Low cloud and visibility
Cloud likely descending through the morning to obscure hills above 600m, with the odd patch down to 400m.This most likely across eastern hills, but also further west. Good visibility is expected away from any rain, however views are likely to become more limited as this occurs, with visibility becoming moderate to poor.
Mountain weather information
Thu 23 May
Sunrise:
Sunset:
Cloudy with summits obscured to start. Outbreaks of rain or drizzle likely easing through the day though remaining mostly cloudy.
Fri 24 May
Sunrise:
Sunset:
Low confidence. Likely drier and brighter with cloud and rain clearing away to the north to leave sunny spells and occasional showers, perhaps thunderstorms.
Sat 25 May
Sunrise:
Sunset:
Moderate confidence. Sunny spells with any early fog patches soon clearing. Perhaps rain and strengthening winds later.
Updated at:
Summit specific forecast
Mountain summit forecast map
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Key
Mountain summits
Other points of interest
Cluster of multiple stations
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.