Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High confidence for some rain and strong winds at times, but with some calmer, drier interludes. Moderate confidence for Thursday's rainfall with the potential for heavy rain and gales.
This evening forecast
Storm Agnes brings persistent, occasionally heavy rain with a risk of thunder, easing later. Storm force, locally higher winds continuing.
Mountain weather hazards
Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.
Gales
Gale force winds (gusts over 50mph) make walking difficult and strenuous with a potential to be blown over by gusts. There is often a marked increase in winds through cols or on exposed ridges and summits. Distances can take longer to cover and compass bearings become harder to follow accurately.
Storm Force Winds
Storm force winds (gusts over 70mph) make walking very strenuous with any mobility virtually impossible over exposed ground. Where these conditions occur there is a high risk of being blown over and even standing may be impossible at times with a risk of being blown off one’s feet. Basic tasks such as using a map, eating, putting on extra clothing or communication become extremely difficult away from any shelter.
Severe Chill Effect
Wind significantly lowers the ‘feels-like’ temperature relative to the actual temperature, with even moderate winds significantly adding to the chilling effect. Strong winds can result in a severe and debilitating wind chill many degrees below the actual temperature. This effect will be enhanced in rain or wet snow. Without protection, prolonged exposure could result in frost nip or frostbite on exposed parts of the body and/or hypothermia.
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.
Heavy Persistent Rain
Heavy and persistent rain can lead to drenched clothing and footwear with waterproofs often becoming soaked through, especially if accompanied by strong winds. This can lead to significant loss of body heat and an increased likelihood of hypothermia. Terrain may turn increasingly boggy underfoot while streams can flood and become impassable. There may also be a risk of flooding in valleys or glens. If there is snow cover, a heightened avalanche hazard is possible and avalanche reports should be consulted where available.
Mountain weather forecast
A blustery, mainly dry, bright day. A risk of persistent rain and strong winds later.
| 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
|
|
Chance of precipitation (at 800m) |
30% | 20% | 10% | 10% | 10% | 20% | 70% | 90% |
Wind direction and speed (mph)
Altitude above mean sea level
| 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|---|---|
| 900m |
SW
46
|
SW
41
|
SW
33
|
SW
31
|
SW
34
|
SW
34
|
S
33
|
S
28
|
| 600m |
SW
33
|
SW
29
|
SW
21
|
SW
22
|
SW
26
|
S
26
|
S
25
|
S
21
|
| 300m |
SW
24
|
SW
20
|
SW
13
|
SW
16
|
S
19
|
S
19
|
S
17
|
S
15
|
| Valley |
SW
23
|
SW
20
|
SW
12
|
SW
13
|
S
17
|
S
18
|
S
16
|
S
14
|
Wind gust (mph)
Altitude above mean sea level
| 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|---|---|
| 900m | 60 | 53 | 43 | 42 | 47 | 48 | 46 | 40 |
| 600m | 47 | 41 | 31 | 32 | 38 | 39 | 37 | 33 |
| 300m | 43 | 38 | 28 | 29 | 34 | 35 | 32 | 29 |
| Valley | 42 | 36 | 24 | 24 | 31 | 33 | 31 | 27 |
Altitude above mean sea level
| 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|---|---|
| 900m |
9°
|
7°
|
6°
|
7°
|
8°
|
8°
|
8°
|
8°
|
| 600m |
11°
|
9°
|
9°
|
10°
|
10°
|
11°
|
10°
|
10°
|
| 300m |
13°
|
12°
|
11°
|
12°
|
13°
|
13°
|
12°
|
12°
|
| Valley |
14°
|
13°
|
13°
|
14°
|
15°
|
15°
|
14°
|
14°
|
| Freezing Level |
2,400m
|
1,900m
|
1,700m
|
1,900m
|
1,800m
|
2,000m
|
2,300m
|
2,600m
|
Altitude above mean sea level
| 00:00 | 03:00 | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|---|---|
| 900m |
3°
|
1°
|
1°
|
2°
|
3°
|
3°
|
2°
|
4°
|
| 600m |
6°
|
5°
|
5°
|
6°
|
6°
|
7°
|
6°
|
6°
|
| 300m |
9°
|
8°
|
8°
|
10°
|
10°
|
10°
|
9°
|
10°
|
| Valley |
10°
|
10°
|
10°
|
12°
|
12°
|
12°
|
11°
|
11°
|
Additional weather information
Meteorologist's view
Winds on summits may exceed those indicated in the tables above, especially into the evening. Walking conditions are expected to be extremely difficult given strong winds and the possibility for heavy, persistent rain into the evening. This would be coupled with poor visibility and a notable wind chill.
Weather
Severe gale to storm force winds continuing overnight, though slowly easing. Mostly cloudy conditions expected along with some drizzle, mainly on western coastal upslopes. Largely dry and bright by day, though a chance for some occasional rain or drizzle on hills. Remaining windy, though not as strong as overnight. Turning cloudier during the afternoon, with a risk for a more persistent and widespread period of rain to develop by the evening. This could be heavy and accompanied by gale force winds on summits.
Chance of cloud-free hill tops
80%, but falling to 50% by the evening.
Low cloud and visibility
Cloud mostly above summits through the morning, but some patches likely on the highest routes at first. A chance for more widespread low cloud to develop by the evening with extensive bases 400-500m and patches below this. Visibility generally good, but becoming moderate or poor if persistent rain develops.
Ground conditions
Please see - https://snowdonia.gov.wales/visit/snowdon/yr-wyddfa-ground-conditions-reports/
Mountain weather information
Weather
Cloud and rain clearing overnight with winds easing. Often dry and bright through the day, just a small chance of drizzle on western slopes during the morning and the odd, blustery afternoon shower developing inland.
Chance of cloud-free hill tops
80%.
Maximum wind speed expected
Westerly 20mph, gusting 30mph.
Temperature
- At 800m Plus 8 degrees Celsius.
- Valley Plus 11 increasing Plus 16 degrees Celsius.
- Freezing level Above summits.
Low cloud and visibility
A few patches of cloud may cover high western summits through the morning, otherwise fine. Visibility away from any areas of morning drizzle will be very good.
Mountain weather information
Sat 30 Sep
Sunrise:
Sunset:
Largely fine to start, though a few valley mist and fog patches are possible early morning. Clouding over later with strengthening southerly winds and a chance persistent rain developing.
Sun 1 Oct
Sunrise:
Sunset:
Overnight rain and strong winds probably clearing early morning. Sunny spells and isolated blustery showers following.
Mon 2 Oct
Sunrise:
Sunset:
Probably rather breezy with a chance of showers, or a long spell of rain during the day.
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.
The region can be divided into four areas with the northernmost area the most popular, including peaks such as Moel Hebog, Mynydd Mawr and the Nantlle Ridge. Many hikers tend to concentrate on Yr Wyddfa (Snowdon) itself regarding it as a fine mountain. However it can become quite crowded, with the peak welcoming around half a million visitors every year, of which four fifths scale the peak on foot, while the remainder choose to take the train instead.
One of Yr Wyddfa's (Snowdon) main attractions is the sheer number and variety of paths that reach the peak. This means that everyone from mountaineering novices to climbing experts should find a way up the mountain that will suit their abilities or provide them with a sufficient test. The easiest is the Llanberis path which, being the longest, has the most shallow ascent. In contrast, the Watkin Path is widely seen as being the most demanding ascent, despite also being considered the prettiest.