Mountain weather

Eryri / Snowdonia

Eryri / Snowdonia Mountain weather forecast table

Confidence

Good confidence for an unsettled day on Tuesday, with heavy rain and showers, lower for rainfall accumulations and extent of thunder risk.

Sunrise:
Sunset:

This evening forecast

Isolated showers linger over southern parts of the park, with some decent sunny spells heading into the evening, gradually becoming cloudier from the west. Breezy.

Sunrise:
Sunset:
Mountain hazards

Mountain weather hazards

Hazards apply at or above 300m, reflecting the more severe conditions which can occur at altitude.

hazard 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.
hazard 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.
hazard 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.
hazard 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.

hazard 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.

Mountain weather forecast

Cloudy with heavy rain, quickly followed by heavy showers and a risk of thunder. Strong to gale-force winds on exposed summits.

Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 800m)
Light rain Light rain Heavy rain Heavy rain Heavy rain Thunder shower (day) Thunder shower (day) Cloudy
Chance of precipitation
(at 800m)
60% 60% 80% 90% >95% 80% 80% 20%

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
36
SW
38
SW
42
SW
43
SW
39
SW
34
W
32
W
32
600m SW
24
SW
27
SW
31
SW
32
SW
29
SW
26
W
22
W
21
300m SW
15
SW
17
SW
20
SW
20
SW
20
SW
18
W
16
W
14
Valley SW
15
S
17
SW
20
SW
20
SW
20
SW
17
W
16
W
15
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 44 47 53 55 51 45 42 40
600m 32 36 41 43 40 36 31 28
300m 28 30 36 37 35 31 28 26
Valley 27 29 35 35 34 29 28 26

Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m
10°
10°
600m
10°
10°
11°
11°
11°
12°
12°
11°
300m
13°
12°
13°
13°
13°
14°
14°
13°
Valley
14°
14°
14°
14°
15°
16°
16°
15°
Freezing Level
2,000m
2,200m
2,400m
2,400m
2,300m
2,300m
2,300m
2,400m

Altitude above mean sea level
Time 00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
900m
600m
300m
10°
10°
10°
10°
11°
12°
11°
Valley
11°
11°
11°
11°
11°
13°
13°
12°

Additional weather information

Meteorologist's view

A tough day in the hills, with gusts reaching 60mph creating hazardous walking conditions and a real risk of being knocked off balance. Navigation may prove difficult, as strong winds combine with low cloud, heavy rain, and the potential for thunder and hail, making it easy for walkers to become disoriented.

Weather

A band of cloud and persistent heavy rain spreads over the park during the morning, driven horizontally by the gale force winds. This will be shortly followed by frequent showers, often heavy with a risk of thunder and possibly some large hail.

Chance of cloud-free hill tops

Less than 10% throughout.

Low cloud and visibility

Overcast cloud is expected during the morning with bases obscuring hills above 100-200m. Visibility is expected to be poor or very poor in cloud and in any heavy downpours. Come the afternoon, there may be a few more breaks in the cloud cover, with bases expected to rise a touch, to around 300-400m. Although this may fall again in heavy showers.

Ground conditions

Please see - https://yrwyddfa.live/

Sunrise:
Sunset:

Mountain weather information

Weather

A cloudy start to the day across the park, although remaining dry. Cloud will gradually begin to break up through the afternoon to see some decent sunny spells. Further cloud and rain will build in from the southwest by the evening.

Chance of cloud-free hill tops

30% becoming 80% by the afternoon.

Maximum wind speed expected

Westerly winds 15mph gusting up to 25mph on summits.

Temperature

  • At 800m Plus 07 Celsius becoming Plus 12 Celsius.
  • Valley Plus 14 Celsius becoming Plus 21 Celsius.
  • Freezing level Well above summits.

Low cloud and visibility

Scattered to broken cloud across the park during the morning, with bases obscuring hills above 500-600m. By the afternoon, cloud will lift and break, with few amounts, well above summits. Sunshine, will turn hazy towards the end of the day, as cloud builds into the evening. Visibilities generally very good, with clear views of distant hills.

Mountain weather information

Thu 17 Jul

Sunrise:
Sunset:

Often cloudy, with some brighter spells possible. Isolated showers, perhaps heavy at times. Fresh to strong south-southwesterly winds.

Fri 18 Jul

Sunrise:
Sunset:

A cloudy start, with sunny spells developing, slight isolated showers possible. Moderate southwesterly winds.

Sat 19 Jul

Sunrise:
Sunset:

Sunny spells and showers. Fresh southwesterly winds.

Updated at:

Summit specific forecast

Mountain summit forecast map

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