Mountain weather
Eryri / Snowdonia Mountain weather forecast table
Confidence
High for a dull and damp start Wednesday to be replaced by clearer conditions with showers later. However confidence is only Moderate for timing of this change, including the timing of the heavier band of rain that moves through as this occurs. High confidence for a day of sunshine and showers Thursday. Confidence is also low with the timing of any rainfall and extent of showers Friday onward.
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.
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.
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.
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.
Mountain weather forecast
Cloudy with heavy rain through the morning. Turning drier with brighter spells in the afternoon, plus the risk of showers.
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
Weather (at 800m) |
|
|
|
|
|
|
Chance of precipitation (at 800m) |
30% | 30% | 80% | 60% | 20% | 30% |
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
|
S
45
|
S
39
|
SW
40
|
SW
40
|
SW
43
|
| 600m |
S
31
|
S
33
|
S
27
|
SW
29
|
SW
29
|
SW
30
|
| 300m |
S
20
|
S
22
|
S
17
|
S
20
|
SW
19
|
SW
19
|
| Valley |
S
20
|
S
22
|
S
17
|
S
20
|
SW
18
|
SW
19
|
Wind gust (mph)
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m | 51 | 56 | 48 | 51 | 51 | 55 |
| 600m | 38 | 43 | 36 | 40 | 39 | 41 |
| 300m | 33 | 39 | 31 | 35 | 35 | 36 |
| Valley | 33 | 37 | 30 | 34 | 33 | 35 |
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
7°
|
6°
|
6°
|
5°
|
3°
|
4°
|
| 600m |
8°
|
8°
|
8°
|
7°
|
6°
|
6°
|
| 300m |
10°
|
10°
|
10°
|
10°
|
8°
|
8°
|
| Valley |
11°
|
12°
|
11°
|
12°
|
10°
|
10°
|
| Freezing Level |
2,000m
|
2,000m
|
1,900m
|
1,400m
|
1,300m
|
1,300m
|
Altitude above mean sea level
| Time | 06:00 | 09:00 | 12:00 | 15:00 | 18:00 | 21:00 |
|---|---|---|---|---|---|---|
| 900m |
0°
|
-1°
|
0°
|
-3°
|
-4°
|
-4°
|
| 600m |
3°
|
3°
|
4°
|
2°
|
0°
|
0°
|
| 300m |
6°
|
7°
|
7°
|
6°
|
4°
|
4°
|
| Valley |
8°
|
8°
|
8°
|
8°
|
6°
|
6°
|
Additional weather information
Meteorologist's view
A very mixed day, with a wide variety of hazards. Poor visibility will be the main issue through the morning, but with some light rain, drizzle and some heavier rain by midday, waterproof layers will also be needed. Winds will be strong, especially later, with gales on highest summits (e.g. Yr Wyddfa), bringing a cold feel in exposure, and a chance of being blown over. Any sunny spells will bring Moderate UV, so appropriate sun protection could also be needed.
Weather
Plenty of low cloud to start, with light rain and drizzle, but some eastern hills could see the odd glimpse of sunshine. Just before midday, a band of heavy rain and gusty winds moves eastwards, clearing early afternoon to sunny spells but also the risk of heavy showers. Staying rather breezy, and windy at times on the summits.
Chance of cloud-free hill tops
10%, rising to 40% during the morning, best chances in the east. Then lifting to 80% from mid-afternoon.
Low cloud and visibility
Cloud will obscure routes and hills above 400m during the morning, but with some western hills seeing cloud as low as 100m at times. This lifting and breaking across eastern hills, but returning to around 400m with heavy rain band moving east after midday. As this clears, many hills will be free of cloud, although the odd patch could linger around 800m. Outside of cloud, moderate to poor visibility is expected through the morning, especially during any rain or drizzle. This will improve to be good to very good by the late afternoon.
Ground conditions
Please see - https://yrwyddfa.live/
Mountain weather information
Weather
Cloudy with showers during the morning with gusty winds on the higher peaks. Cloud will lift through the morning into the afternoon as showers become more isolated and ease by midday. Winds become lighter into the afternoon and evening.
Chance of cloud-free hill tops
40% but lifting through the afternoon to 80%.
Maximum wind speed expected
Southwesterly 40mph gusting 50-55mph early hours, but easing to 30-35mph gusting 40-45mph
Temperature
- At 800m Plus 5 Celsius, rising to Plus 9 Celsius.
- Valley Plus 10 Celsius, rising to Plus 13 Celsius.
- Freezing level Above summits.
Low cloud and visibility
Cloud will obscure routes and hills above 300m at first before lifting and breaking through the morning, to become more broken at 800m. Outside of cloud, moderate to poor visibility is expected through the morning, especially during any rain or drizzle. This will improve to be good to very good by the late afternoon.
Mountain weather information
Fri 17 Apr
Sunrise:
Sunset:
Cloudier start with outbreaks of rain and drizzle, perhaps the odd heavier burst. This most likely during the afternoon with a band of heavy rain moving through. Freezing level staying above the summits.
Sat 18 Apr
Sunrise:
Sunset:
Sunny spells and showers, which could include the odd burst of sleet or snow on very highest tops. Likely staying breezy, with strong gusts near any showers. Freezing level falling to around 1000m.
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. Freezing level staying above the summits.
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.