Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for largely fine conditions Monday, also high for showers on Tuesday though details uncertain. Confidence in the detail Wednesday onward is low, but high for the overall theme of often fine with warm sunshine, but with the ongoing potential for showers. Moderate confidence for the chance of a spell of more persistent rain early Thursday.
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
Variable cloud and sunny spells. Perhaps the odd heavy shower.
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
00% | <05% | 10% | 20% | 10% | <05% |
Wind direction and speed (mph)
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
NE
7
|
E
7
|
E
7
|
NE
7
|
NE
10
|
E
13
|
| 600m |
E
5
|
N
7
|
N
7
|
E
5
|
N
5
|
E
9
|
| 300m |
E
3
|
N
5
|
N
6
|
NE
5
|
NE
5
|
E
6
|
| Valley |
E
3
|
N
6
|
N
6
|
NE
6
|
N
5
|
E
6
|
Wind gust (mph)
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m | 10 | 11 | 11 | 11 | 14 | 18 |
| 600m | 7 | 11 | 11 | 9 | 9 | 14 |
| 300m | 5 | 9 | 10 | 9 | 9 | 13 |
| Valley | 5 | 9 | 10 | 11 | 10 | 13 |
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
11°
|
11°
|
12°
|
12°
|
11°
|
10°
|
| 600m |
13°
|
14°
|
14°
|
14°
|
14°
|
12°
|
| 300m |
14°
|
16°
|
17°
|
17°
|
16°
|
14°
|
| Valley |
15°
|
17°
|
18°
|
18°
|
17°
|
15°
|
| Freezing Level |
2,400m
|
2,400m
|
2,400m
|
2,400m
|
2,400m
|
2,300m
|
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
10°
|
10°
|
11°
|
11°
|
10°
|
7°
|
| 600m |
12°
|
12°
|
13°
|
13°
|
13°
|
10°
|
| 300m |
14°
|
15°
|
16°
|
16°
|
16°
|
13°
|
| Valley |
15°
|
16°
|
17°
|
17°
|
17°
|
14°
|
Additional weather information
Meteorologist's view
A largely fine day and with High UV, appropriate sun protection is essential. The odd heavy shower cannot be completely ruled out though, so packable waterproofs will be useful.
Weather
Variable cloud and warm sunny spells throughout the day, with cloud most extensive across northern and eastern hills. This potentially thick enough for the odd heavy shower, with a low chance of the odd rumble of thunder. Most hills and routes remaining dry, especially those further south.
Chance of cloud-free hill tops
90%
Low cloud and visibility
Cloud persisting above summits for much of the day, though the odd scrap could descent to around 900m alongside any showers. Very good views expected for much of the day, with hills in excess of 25km away likely visible from the tops. However, this falling to a few km's during any heavy rain.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Dry through Tuesday morning with variable cloud and clear spells, but also turning chilly again in sheltered valleys by dawn. A largely fine, sunny start but cloud building more extensively than on Monday. This leading to a greater chance of heavy and perhaps thundery showers developing through the afternoon.
Chance of cloud-free hill tops
90%
Maximum wind speed expected
Easterly 5-10mph
Temperature
- At 800m Plus 9 Celsius rising to Plus 16 Celsius
- Valley Plus 4 Celsius rising to Plus 21 Celsius
- Freezing level Above summits
Low cloud and visibility
Cloud remaining largely above the summits, with just the odd patch down to 900m during and heavy or thundery showers. Very good views persisting away from showers, likely in excess of 25km, but falling to a few km during any heavy rain.
Mountain weather information
Wed 22 May
Sunrise:
Sunset:
Some early mist or fog patches in valleys soon lifting. A rather cloudy day follows, but also some hazy sunshine likely, especially towards the southwest. Most hills staying dry, but isolated showers possible.
Thu 23 May
Sunrise:
Sunset:
Likely cloudier and breezier start, with some hills obscured, along with outbreaks of rain or drizzle. This easing through the morning with some warm sunny spells developing.
Fri 24 May
Sunrise:
Sunset:
Low confidence, but likely a similar day to Wednesday, with early mist patches clearing to hazy sunny spells. Chance of isolated showers.
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.