Mountain weather

Bannau Brycheiniog / Brecon Beacons

Yellow warning

Yellow weather warning in force for Bannau Brycheiniog / Brecon Beacons

Bannau Brycheiniog / Brecon Beacons Mountain weather forecast table

Confidence

High for a wet start and very windy day Tuesday and for generally mild, unsettled and often windy conditions continuing through into the weekend, but lower for timings of arrival and clearance of more persistent bands of rain.

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 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.
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 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.

Mountain weather forecast

Wet morning, becoming drier through afternoon. Very windy.

Time 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 600m)
Heavy rain Heavy rain Heavy rain Cloudy Heavy shower (night) Heavy shower (night)
Chance of precipitation
(at 600m)
80% 70% 60% 20% 30% 30%

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
40
S
39
S
41
SW
39
SW
33
SW
31
300m S
22
S
22
S
23
SW
23
SW
20
SW
18
Valley S
17
S
17
S
20
SW
20
SW
16
SW
14
Wind gust (mph)
Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
600m 48 48 52 51 44 42
300m 45 45 47 47 41 37
Valley 42 42 45 44 37 34

Altitude above mean sea level
Time 06:00 09:00 12:00 15:00 18:00 21:00
600m
10°
10°
10°
300m
11°
12°
12°
11°
Valley
12°
12°
13°
12°
10°
10°
Freezing Level
3,200m
3,200m
2,900m
1,800m
1,400m
1,300m

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

Additional weather information

Meteorologist's view

Despite relative mild conditions, with heavy rain and winds increasing to gust around 60-70mph over ridges and summits, there will be a significant chill effect.

Weather

Windy throughout, with significant buffeting over exposed ground. A wet morning with heavy rain turning lighter into the afternoon before eventually clearing from the west. More showery conditions are then expected with some drier intervals, although any late brightness will be limited. Heavier showers may develop into the evening, mainly affecting the west. It will be very wet underfoot with swollen watercourses.

Chance of cloud-free hill tops

Little chance through the morning improving to 60% through the afternoon, then improving further though the late afternoon and evening.

Low cloud and visibility

Periods or persistent cloud above 450m to 600m, with patches below through the morning, lifting and becoming occasional above 600-750m in the afternoon, the cloud then becoming widely occasional through the late afternoon and evening. Away from cloud, visibility good falling to several kilometres in rain, becoming very good in the evening.

Recent rainfall

Location: Neuadd (Near Pontsticill)
Altitude: 353m
Last 24 hoursLast 48 hoursLast 72 hours
19.2mm30.8mm62.4mm
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

Occasionally heavy showers and clear spells through the early hours. Then a bright day with sunny spells and, especially through the morning, occasional showers. Dry with clear spells through the evening.

Chance of cloud-free hill tops

Around 60%

Maximum wind speed expected

Southwesterly 25-30mph, with gusts around 45mph over higher peaks.

Temperature

  • At 600m Around plus 7 or 8 Celsius
  • Valley Around plus 7 or 8 Celsius rising to plus 11 or 12 Celsius by day
  • Freezing level Above the summits

Low cloud and visibility

Occasional or periods of cloud above 600-750m. Away from cloud visibility very good or excellent, falling briefly in showers.

Mountain weather information

Thu 11 Dec

Sunrise:
Sunset:

Rather cloudy with, especially in the afternoon, patchy rain and drizzle. Occasionally strong southwesterly winds. Freezing level above the summits.

Fri 12 Dec

Sunrise:
Sunset:

Band of occasionally heavy rain pushes east in morning then a dry afternoon with sunny spells. Occasionally strong southerly or southwesterly winds easing later. Freezing level above summits.

Sat 13 Dec

Sunrise:
Sunset:

Dry, bright start but becoming cloudy with outbreaks of afternoon rain. Strengthening southwesterly winds. Freezing levels above the summits.

Updated at:

Summit specific forecast

Mountain summit forecast map

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