Mountain weather

Bannau Brycheiniog / Brecon Beacons

Yellow warning

Yellow weather warnings in force for Bannau Brycheiniog / Brecon Beacons

Bannau Brycheiniog / Brecon Beacons Mountain weather forecast table

Confidence

High for Wednesday, and for a generally unsettled rest of the week. Some uncertainty in the position of heavy rain and strength of winds on Thursday, and for position of rain bands over 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 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 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.

Mountain weather forecast

Rain soon turning heavy and persistent. Strong summit winds.

Time 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 600m)
Cloudy Light rain Heavy rain Heavy rain Heavy rain Heavy rain
Chance of precipitation
(at 600m)
<05% 80% >95% >95% >95% 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 S
28
S
34
S
32
S
31
S
32
SW
31
300m S
15
S
20
S
19
S
19
S
19
SW
19
Valley SW
11
SW
16
S
14
S
16
S
16
SW
16
Wind gust (mph)
Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
600m 36 44 41 40 41 41
300m 32 41 39 39 39 38
Valley 29 37 33 37 37 36

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

Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
600m
-4°
-3°
-2°
300m
Valley

Additional weather information

Meteorologist's view

Gusts of 50-55 mph likely over the higher summits for much of the day. Heavy rain will result in very wet underfoot conditions with high watercourses making any river crossings hazardous. Some flooding of footpaths and access roads is possible.

Weather

Rain spreading from the west, turning heavy late morning. Heavy rain persisting through the afternoon and much of the evening with strong winds, approaching gale force over the summits. Turning largely dry around midnight.

Chance of cloud-free hill tops

60% early morning, soon falling to nil.

Low cloud and visibility

Good visibility with cloud above the summits at first, but quickly lowering, bases dropping to 400m by late morning with very poor visibility for the rest of the day.

Recent rainfall

Location: Neuadd (Near Pontsticill)
Altitude: 353m
Last 24 hoursLast 48 hoursLast 72 hours
0.8mm20mm26mm
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

Dry but cloudy through the early hours. Outbreaks of occasionally heavy rain spreads north in the morning, clearing around late afternoon or early. Turning drier with the odd shower and clear spells late evening.

Chance of cloud-free hill tops

50% becoming 10% during the evening.

Maximum wind speed expected

Southwest becoming south around dawn, 20 gusting 30 mph. Increasing to 40 gusting 50-55 mph by early afternoon. Winds becoming southwest in the evening.

Temperature

  • At 600m Plus 6 or 7 Celsius, falling to plus 1 Celsius late evening.
  • Valley Plus 8 Celsius rising to 10 Celsius.
  • Freezing level Above the summits, falling to 1000m late evening.

Low cloud and visibility

Very poor visibility with cloud extensive to lower slopes for much of the day, lifting to around 500m from mid-afternoon. Hills becoming cloud free in the evening.

Mountain weather information

Fri 19 Dec

Sunrise:
Sunset:

A bright and breezy day with a few well scattered showers. Fresh southwest winds and feeling colder than recent days, although freezing level above the summits.

Sat 20 Dec

Sunrise:
Sunset:

After a dry start rain will turn persistent and occasionally heavy. Strong south or southwest winds. Freezing level above the summits.

Sun 21 Dec

Sunrise:
Sunset:

A generally cloudy day with hill fog and outbreaks of rain at times. Moderate generally southerly winds. Freezing level remaining above the summits.

Updated at:

Summit specific forecast

Mountain summit forecast map

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