Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High confidence for mostly fine and much warmer conditions to develop this week. Moderate confidence for cloud and rain detail on Tuesday.
This evening forecast
Mostly cloudy with isolated rain or drizzly showers, mainly in the west. These fading through the evening. Generally light winds, but locally breezy at higher elevations.
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.
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.
Mountain weather forecast
Dry with plenty of sunshine, though winds strengthening through the day.
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
|
|
Chance of precipitation (at 800m) |
<05% | <05% | <05% | <05% | <05% | <05% | <05% | <05% |
Wind direction and speed (mph)
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
SW
16
|
W
15
|
W
18
|
SW
17
|
SW
18
|
SW
21
|
SW
23
|
SW
26
|
| 600m |
SW
10
|
SW
8
|
SW
9
|
SW
13
|
SW
18
|
SW
20
|
SW
20
|
SW
21
|
| 300m |
SW
6
|
SW
4
|
SW
4
|
SW
9
|
SW
13
|
SW
14
|
SW
14
|
SW
13
|
| Valley |
SW
6
|
SW
5
|
SW
4
|
W
9
|
SW
12
|
SW
14
|
SW
14
|
SW
14
|
Wind gust (mph)
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m | 19 | 18 | 22 | 22 | 25 | 28 | 31 | 33 |
| 600m | 13 | 11 | 12 | 18 | 24 | 28 | 28 | 28 |
| 300m | 11 | 9 | 8 | 16 | 21 | 23 | 23 | 24 |
| Valley | 11 | 10 | 8 | 14 | 20 | 23 | 23 | 25 |
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
9°
|
9°
|
8°
|
9°
|
10°
|
10°
|
9°
|
8°
|
| 600m |
12°
|
10°
|
10°
|
12°
|
12°
|
12°
|
11°
|
10°
|
| 300m |
13°
|
12°
|
12°
|
14°
|
16°
|
15°
|
14°
|
12°
|
| Valley |
14°
|
13°
|
14°
|
16°
|
17°
|
17°
|
15°
|
13°
|
| Freezing Level |
2,600m
|
2,500m
|
2,800m
|
2,900m
|
2,900m
|
2,800m
|
2,600m
|
2,500m
|
Altitude above mean sea level
| Time | 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|---|---|
| 900m |
6°
|
6°
|
5°
|
6°
|
7°
|
6°
|
4°
|
3°
|
| 600m |
10°
|
9°
|
8°
|
9°
|
9°
|
9°
|
7°
|
6°
|
| 300m |
12°
|
12°
|
12°
|
13°
|
13°
|
13°
|
11°
|
10°
|
| Valley |
14°
|
13°
|
14°
|
15°
|
15°
|
14°
|
13°
|
11°
|
Additional weather information
Meteorologist's view
Adequate sun protection will be required given forecast High UV levels on Monday. Be wary that strengthening winds through the day may act to mask the perceived strength of the sunshine. From late afternoon onwards brisk winds at higher elevations could cause some buffeting and more challenging walking conditions near summits and ridges.
Weather
Dry overnight, some patchy cloud covering higher summits at times. Plenty of sunshine during the early morning away from windward slopes but occasional fair weather cloud building by midday, along with a strengthening breeze. Cloud generally dissipating through the latter part of the afternoon to leave a mostly sunny evening, however some low cloud may return to elevated parts of the Yr Wydffa range where it will also become rather windy.
Chance of cloud-free hill tops
60% improving to 95% by late morning. Becoming 80% from early evening.
Low cloud and visibility
Occasional patches of cloud mainly on western slopes overnight and early morning. Bases variable, but largely above 500m but lifting clear of all summits by late morning or very early afternoon. Some patchy cloud returning in the evening, mainly across the Yr Wyddfa range with bases above 500m. Visibilities generally very good or excellent, outside of any summit cloud.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Occasional bright spells possible in the east during the morning but likely cloudier with drizzle on some western slopes. Probably more widely cloudy through the afternoon and evening, along with a chance of more persistent rain or drizzle developing for a time, however timings of the associated weather system are somewhat uncertain. Occasional strong winds at higher elevations though generally easing through the day.
Chance of cloud-free hill tops
30%
Maximum wind speed expected
Southwesterly 25-30mph with gusts 35-40mph.
Temperature
- At 800m Plus 10 degrees Celsius.
- Valley Plus 8 increasing to Plus 17 degrees Celsius.
- Freezing level Above summits.
Low cloud and visibility
Low cloud probably confined to higher summits initially (above around 600-700m), but lowering, especially in the west with time to around 500m at times in rain or drizzle. There is a chance for lower bases on windward western slopes during the afternoon and evening. The greatest chance for cloud breaks and higher cloud bases will be across the east of the park. Visibility generally very good, but occasionally moderate or locally poor outside of cloud where rain or drizzle develop.
Mountain weather information
Wed 18 Jun
Sunrise:
Sunset:
Early cloud clearing to a dry and largely sunny day. Generally moderate south to southwesterly winds.
Thu 19 Jun
Sunrise:
Sunset:
Dry, very warm and sunny. Light to moderate south to southeasterly winds.
Fri 20 Jun
Sunrise:
Sunset:
Good sunny spells and warm or very warm. Chance of daytime showers developing. Winds mainly from the south and light or moderate in strength.
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.