Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for approach of frontal feature through this evening with moderate confidence on expected timings of rain band arriving tomorrow. High in change to more settled conditions into the weekend.
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.
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.
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 cloudy start with patchy rain and drizzle. Heavier rain then arriving from the west with clearer spells to follow.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
80% | 40% | 10% | <05% | <05% | <05% |
Wind direction and speed (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
S
43
|
SW
35
|
SW
35
|
SW
37
|
SW
38
|
SW
35
|
| 600m |
S
30
|
SW
26
|
SW
27
|
SW
29
|
SW
27
|
SW
23
|
| 300m |
S
19
|
SW
16
|
SW
19
|
SW
20
|
SW
18
|
SW
16
|
| Valley |
S
19
|
SW
16
|
SW
18
|
SW
19
|
SW
17
|
SW
15
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 50 | 43 | 45 | 47 | 48 | 43 |
| 600m | 37 | 33 | 36 | 38 | 36 | 32 |
| 300m | 33 | 27 | 32 | 34 | 32 | 29 |
| Valley | 33 | 26 | 31 | 33 | 31 | 27 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
5°
|
5°
|
4°
|
4°
|
3°
|
3°
|
| 600m |
7°
|
7°
|
7°
|
7°
|
6°
|
5°
|
| 300m |
9°
|
9°
|
10°
|
10°
|
9°
|
8°
|
| Valley |
10°
|
11°
|
12°
|
12°
|
10°
|
9°
|
| Freezing Level |
2,000m
|
1,400m
|
1,300m
|
1,300m
|
1,200m
|
1,400m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
-2°
|
-2°
|
-2°
|
-3°
|
-4°
|
-4°
|
| 600m |
2°
|
2°
|
2°
|
1°
|
0°
|
0°
|
| 300m |
6°
|
6°
|
7°
|
6°
|
5°
|
4°
|
| Valley |
7°
|
8°
|
8°
|
8°
|
7°
|
6°
|
Additional weather information
Meteorologist's view
Poor conditions initially with navigation challenging due to low cloud and outbreaks of heavy rain. Due to this waterproof layers are recommended for any outdoor activity. Winds on the highest peaks are also expected to be 5-10mph higher than the table stated above which may make walking challenging at times, this will also bring a rather severe wind chill so multiple warm layers are recommended through the day. Visibility conditions improve through the afternoon with outdoor activities becoming more enjoyable and view of distant summits becoming possible.
Weather
Patchy rain and drizzle at first before a band of heavier rain arrives from the west around dawn. This is expected to bring some heavier bursts of rain, particularly over high ground. Once this clears away to the east skies are expected to brighten with sunny spells developing for afternoon, before patchy cloud pushes in after nightfall.
Chance of cloud-free hill tops
10% gradually increasing to 80% through the afternoon before decreasing to 30% as evening approaches.
Low cloud and visibility
Cloud bases initially obstructing routes and peaks above 500m. Cloud bases then expected to gradually lift above summits and break as the afternoon progresses. Through late evening and into the overnight, cloud bases are expected to drop once again to 500-700m, mainly to the north and west of the park. Visibilities are expected to be good or moderate outside of any cloud or rain initially, with poor or very poor visibilities expected in heavier rain and extensive hill fog. Through the afternoon visibilities are expected to become very good or excellent with views to distant peaks, before conditions deteriorate once again after nightfall.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
A drier and brighter day ahead with a risk of an isolated light shower through the first part of the day. Patchy cloud likely throughout, but quickly lifting above summits.
Chance of cloud-free hill tops
30% soon increasing to 90%.
Maximum wind speed expected
Westerly 25-30mph.
Temperature
- At 800m Plus 2 Celsius.
- Valley Plus 7 Celsius rising to Plus 10 Celsius.
- Freezing level Above summits.
Low cloud and visibility
Patchy cloud likely to shroud the highest peaks at times to start with cloud bases of 300-500m, slowly rising through the morning to heights above summits through the afternoon and into the evening.
Mountain weather information
Sun 19 Apr
Sunrise:
Sunset:
A largely dry day, with light winds. Early brighter or sunny spells are likely to turn hazy as high cloud builds, however summits are likely to remain clear. Mist and fog patches to start. Freezing level 800-1000m.
Mon 20 Apr
Sunrise:
Sunset:
Another fine and dry day ahead with plenty of sunny spells throughout. Winds are expected to remain light. Freezing levels 800-1000m to start rising above summits through the afternoon.
Tue 21 Apr
Sunrise:
Sunset:
A rather settled day ahead with increased cloud compared to the previous days and the potential for outbreaks of isolated light showers. Light winds throughout with freezing levels 800-1000m.
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.