Mountain weather

Bannau Brycheiniog / Brecon Beacons

Bannau Brycheiniog / Brecon Beacons Mountain weather forecast table

Confidence

High for unsettled, often wintry conditions throughout the forecast period, including a period of very strong winds on Thursday. Lower for the snow-level on Friday, and the timings of arrival and clearance of more persistent bands of rain and snow, especially by the weekend.

Sunrise:
Sunset:
Mountain hazards

Mountain weather hazards

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

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 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 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.
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.

Mountain weather forecast

Very windy with heavy rain spreading south after dark.

Time 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 600m)
Overcast Overcast Light rain Heavy rain Heavy rain Heavy rain
Chance of precipitation
(at 600m)
30% 30% 60% 90% 90% 90%

Wind direction and speed (mph)
Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
600m SW
34
SW
34
SW
40
SW
40
SW
39
SW
30
300m SW
19
SW
21
SW
23
SW
24
SW
23
SW
17
Valley SW
16
SW
17
SW
19
SW
20
SW
19
SW
14
Wind gust (mph)
Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
600m 44 44 51 52 50 40
300m 40 43 47 48 48 35
Valley 37 40 44 44 44 32

Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
600m
300m
10°
10°
10°
Valley
10°
10°
10°
Freezing Level
1,400m
1,900m
2,100m
2,000m
1,900m
1,700m

Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
600m
-2°
300m
Valley

Additional weather information

Meteorologist's view

Gusts are likely to exceed 60mph over the highest routes and ridges, with some sudden gusts through the evening. Even for lower level walks progress is likely to be impeded times. Warm waterproof layers essential.

Weather

A cloudy morning with outbreaks of rain. These turning persistent through the afternoon, and then briefly heavier during the evening. Winds also strengthening throughout, becoming very strong and gusty for time.

Chance of cloud-free hill tops

10% in west, 30% in the east.

Low cloud and visibility

Cloud obscuring hills above 500m in the west, but more occasional with routes above 750m clear in the east. Some patches possible down to 400m during heaviest rain during the evening. Outside of cloud, visibility will be good falling to several kilometres in rain and drizzle.

Recent rainfall

Location: Neuadd (Near Pontsticill)
Altitude: 353m
Last 24 hoursLast 48 hoursLast 72 hours
0mm11.2mm14mm
Measurement date:

Rainfall data provided by Natural Resources Wales. The Met Office is not responsible for content provided by third parties and may remove this data without warning.

Sunrise:
Sunset:

Mountain weather information

Weather

Overnight heavy rain and very strong winds will ease away to give clear spells, but will also bring lower freezing levels and perhaps some icy routes to start. Sunny spells and isolated showers are then expected, falling as snow above 500m. While not as windy as Thursday, it will still be breezy, with a notable chill. This snow level rising to around 700m after dark.

Chance of cloud-free hill tops

80% by day, but 30% early and late.

Maximum wind speed expected

Westerly 25mph gusting 30-40mph.

Temperature

  • At 600m Zero Celsius rising to Plus 2 Celsius
  • Valley Plus 4 Celsius rising to Plus 8 Celsius
  • Freezing level 600m rising to 800m during the evening.

Low cloud and visibility

Overnight cloud, obscuring routes above 500m will clear through the early hours. Cloud then largely above summit level, although the odd patch could obscure routes above 600m with showers. Chance of more extensive cloud moving in after dark, again obscuring tops above 500m. Outside of cloud, visibility will be very good falling to around 5-10 kilometres in heavy rain, and a kilometre or so in any snow.

Mountain weather information

Sat 14 Mar

Sunrise:
Sunset:

A few early showers then mainly dry with sunny spells. Cloud increasing through the evening. Occasionally strong westerly winds backing southwesterly and easing. Freezing level around 800m.

Sun 15 Mar

Sunrise:
Sunset:

Cloudy with rain, preceded by snow on higher summits, clearing to sunny spells and blustery wintry showers in afternoon. Windy with summit gales. Freezing level above summits, falling to 600m later.

Mon 16 Mar

Sunrise:
Sunset:

Early wintry showers dying out with sunny spells developing but cloud and rain spreading east in afternoon. Strong westerly winds, summit gales, easing. Freezing level 600m, rising later.

Updated at:

Summit specific forecast

Mountain summit forecast map

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