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Snowdonia - Mountain weather forecast

Weather warnings

Warnings affecting Snowdonia over the next 5 days

Confidence

High for timings of the rain clearance today. Low for details over the rain for Sunday and Monday, with large uncertainty over positions of weather fronts due to expected slow-moving nature.

  • Thursday
  • Friday
  • Further outlook

Thursday 21 September 2017

Weather hazards

Poor visibility High likelihood Hide detail

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.

Learn more about poor visibility

Gales Medium likelihood Show detail

Progress will be impeded by very strong winds. Walking will be difficult and strenuous at times with a potential for one to be blown over in gusts. There can be a marked increase in winds through cols or on exposed ridges and summits. Distances often take longer to cover with compass bearings becoming more difficult to follow accurately.

Learn more about gales

Heavy persistent rain Low likelihood Show detail

Prolonged exposure to heavy rain can result in drenched clothing and a risk of hypothermia if not wearing good quality waterproofs. Terrain may turn increasingly boggy underfoot, while mountain streams will rapidly rise into spate and may 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.

Learn more about heavy persistent rain

Forecast

Outbreaks of rain, occasionally heavy. Drier later with some sunny spells.

Weather

06:00 09:00 12:00 15:00 18:00 21:00
Weather at 800m Heavy rain Heavy rain Light rain Sunny intervals Sunny day Clear night
Chance of precipitation at 800m 80% 80% 60% 20% 10% 00%

Wind speed and direction

06:00 09:00 12:00 15:00 18:00 21:00
Altitude above mean sea level
900m SW 33 42 NW 14 20 W 15 20 W 17 23 SW 15 19 SW 20 26
600m SW 22 31 NW 11 16 W 12 17 W 13 20 SW 10 13 SW 13 19
300m SW 15 29 NW 7 15 W 8 16 W 8 18 SW 4 11 SW 7 16
Valley S 15 30 NW 17 27 W 14 24 W 16 28 SW 10 19 SW 11 19

Temperature

06:00 09:00 12:00 15:00 18:00 21:00
Altitude above mean sea level
900m 10 ° 7 ° 7 ° 6 ° 5 ° 6 °
600m 11 ° 9 ° 9 ° 8 ° 8 ° 8 °
300m 12 ° 11 ° 11 ° 11 ° 10 ° 10 °
Valley 13 ° 12 ° 13 ° 13 ° 11 ° 10 °

Feels like temperature

06:00 09:00 12:00 15:00 18:00 21:00
Altitude above mean sea level
900m 5 ° 4 ° 3 ° 1 ° 1 ° 1 °
600m 8 ° 6 ° 6 ° 5 ° 5 ° 5 °
300m 10 ° 9 ° 9 ° 10 ° 10 ° 8 °
Valley 12 ° 10 ° 11 ° 11 ° 10 ° 8 °

Freezing level

06:00 09:00 12:00 15:00 18:00 21:00
Freezing level i 2,700 m 2,400 m 1,900 m 1,500 m 1,400 m 1,500 m
Sunrise: 07:00
Sunset: 19:18
Moon phase: New

Weather

A cloudy morning with outbreaks of heavy rain and drizzle, accompanied with strong southwesterly winds initially, and cloud shrouding many of the higher tops. The rain should ease later in the afternoon as the weather front edges eastwards, clearing western parts first. Winds will also quickly ease right down and veer westerly as it clears. Some late sunny spells seem likely before dusk.

Chance of cloud-free mountain/hill tops at 800m

Less than 10% at first as cloud affects all areas, with bases down to 300 metres widely. Bases lifting to around 500 metres, but still with a 10% chance above 500 metres. Quickly rising to 90% during the afternoon, as the rain eases and the cloud breaks.

Visibility

Poor or very poor at first as the heavy rain perhaps obscures nearby hills, together with low cloud. Rising to good or very good in the winds later as the rain eases and cloud rises.

Meteorologist's view

Moderate risk of gale gusts first thing due to local funnelling effects, but winds should ease quickly. Becoming much cooler and less humid with the westerly wind behind the weather front.

Ground conditions

No adverse ground conditions reported on 21 of Sep

Friday 22 September 2017

Sunrise: 07:01
Sunset: 19:16
Moon phase: New

Weather

A dry, cold and bright start, but it will become increasingly cloudy, with rain pushing east by midday. Chance of local gale force gusts over high tops. The rain should turn lighter and more drizzly as the afternoon goes on, but cloud is expected to lower onto high ridges reducing visibility. Winds should also ease.

Temperature

  • At 800m Plus 6 Celsius becoming Plus 8.
  • Valley Plus 5 rising to plus 17 Celsius.
  • Freezing level Above the summits.

Visibility

Very good at first, but falling to moderate or poor in the rain and low cloud, making even near ridges difficult to see.

Chance of cloud-free mountain/hill tops at 800m

90% at first, but falling to 10% by early afternoon as the heavier rain arrives bringing bases down to 400 metres in places. Rising to 80% again as the rain clears, although some patchy cloud may continue to affect tops above 600 metres.

Maximum wind speed expected

Southerly 55mph until 0900, then west or southwesterly 30mph.

Saturday 23 September 2017

Sunrise: 07:03
Sunset: 19:13
Moon phase: New

Low cloud and perhaps light drizzle early morning, but this should thin and break during the day allowing plenty of warm sunshine to develop, especially during the afternoon. Moderate to strong southerly winds at altitude.

Sunday 24 September 2017

Sunrise: 07:05
Sunset: 19:11
Moon phase: New

Variable amounts of cloud and sunny periods through the day, with most of the cloud above the hills. Occasional rain, perhaps heavy, is likely to edge slowly eastwards during the afternoon, affecting all parts overnight.

Monday 25 September 2017

Sunrise: 07:07
Sunset: 19:09
Moon phase: Waxing crescent

Perhaps some rain lingering, with considerably uncertainty at this stage. There is also an equal chance of some good sunny intervals. Winds look to be light and it should be rather warm.

Issued at:
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The 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.

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