Mountain weather
Snowdonia Mountain weather forecast table
Confidence
High confidence for a spell of wet and windy weather during Friday evening and much of Saturday. Medium confidence of drier and brighter weather from Sunday onwards.
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.
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.
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.
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.
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
Heavy rain and gale force winds developing during Friday evening.
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
30% | 60% | 60% | 30% | 60% | 60% |
Wind direction and speed (mph)
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
S
41
|
S
39
|
SW
27
|
SW
31
|
S
37
|
S
46
|
| 600m |
S
29
|
S
30
|
SW
20
|
SW
25
|
S
28
|
S
34
|
| 300m |
S
19
|
S
20
|
SW
12
|
SW
14
|
S
16
|
S
18
|
| Valley |
S
19
|
S
20
|
SW
12
|
SW
14
|
S
16
|
S
17
|
Wind gust (mph)
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m | 48 | 47 | 35 | 41 | 48 | 59 |
| 600m | 36 | 37 | 28 | 35 | 38 | 46 |
| 300m | 33 | 33 | 26 | 31 | 34 | 40 |
| Valley | 33 | 33 | 26 | 29 | 34 | 38 |
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
3°
|
3°
|
4°
|
2°
|
2°
|
2°
|
| 600m |
5°
|
5°
|
5°
|
4°
|
4°
|
4°
|
| 300m |
7°
|
8°
|
7°
|
7°
|
6°
|
7°
|
| Valley |
8°
|
9°
|
9°
|
9°
|
7°
|
8°
|
| Freezing Level |
1,200m
|
1,400m
|
1,400m
|
1,100m
|
1,200m
|
1,100m
|
Altitude above mean sea level
| 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 | |
|---|---|---|---|---|---|---|
| 900m |
-6°
|
-4°
|
-3°
|
-5°
|
-7°
|
-7°
|
| 600m |
-2°
|
-1°
|
0°
|
-2°
|
-3°
|
-3°
|
| 300m |
3°
|
3°
|
4°
|
4°
|
2°
|
2°
|
| Valley |
4°
|
5°
|
6°
|
6°
|
4°
|
4°
|
Additional weather information
Weather
A spell of heavy rain will move eastwards this morning, with the heaviest rain on western upslopes. A brief drier and brighter interlude will then develop during the middle of the afternoon, before the weather begins to deteriorate just before dusk. Spells of heavy rain and gale force winds are likely for the rest of the evening.
Chance of cloud-free mountain/hill tops at 800m
60% decreasing to 30% during the passage of rain during the morning and evening.
Ground conditions
No recent ground conditions report available. For archived reports see - http://www.snowdonia.gov.wales/visiting/walking/ground-conditions
Visibility
Generally good, but falling to just a few km during the spells of rain. Very poor in fog at higher altitudes in rain.
Meteorologist's view
The heavy rainfall and strong winds combined during the evening are likely to give a severe chill effect, with a chance of the rain turning to sleet at times across the highest summits.
Mountain weather information
Weather
Wet and windy with gale to severe gale force winds expected through most of the day. Further heavy showery rain is likely during the afternoon, but drier and less windy weather is likely to move in from the west during the evening.
Chance of cloud-free mountain/hill tops at 800m
Cloud cover from around 300m during the morning, but temporarily improving to around 600m at times. Cloud tending to lift to around 600m during the afternoon, and rising above the mountain tops just before dusk.
Maximum wind speed expected
Southwesterly quickly veering Westerly or northwesterly 40-50 mph, gusting to 60-65mph, easing to 30-40 mph by dusk.
Temperature
- At 800m Plus 02 Celsius rising to PS05 Celsius
- Valley Plus 6 Celsius increasing to Plus 11 Celsius during the afternoon.
- Freezing level Above summits
Visibility
Generally between 2 to 5 km during the morning, but temporarily improving in any drier interludes. Visibilities improving more generally during the afternoon, with some good vistas expected towards dusk.
Mountain weather information
Sunday 28 April
Sunrise:
Sunset:
Dry with clear spells early Sunday with winds easing. After dawn it will remain dry with some scattered cloud temporarily covering the highest summits. The afternoon seeing some brief sunny spells, before cloud begins to lower with some patchy drizzle in the evening. Freezing levels above the summits.
Monday 29 April
Sunrise:
Sunset:
The early hours of Monday morning will see some scattered low cloud down to 400m with some patchy drizzle. Conditions improving during the morning, with cloud lifting above the summits by the afternoon with some spells of sunshine. Winds fairly light with freezing levels well above the summits.
Tuesday 30 April
Sunrise:
Sunset:
After any early morning low cloud, Tuesday will be a dry day with some spells of strong sunshine. Feeling a little warmer than previous days, with light winds and freezing levels way above the summits.
Updated at:
Summit specific forecast map
Summit specific forecasts for SnowdoniaThe Snowdonia mountains are made up of 90 mountain peaks including the tallest mountain in Wales, 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 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 Snowdon’s 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.