Mountain weather

Bannau Brycheiniog / Brecon Beacons

Bannau Brycheiniog / Brecon Beacons Mountain weather forecast table

Confidence

High for the general story and an increasingly settled period. Moderate for the timing of the heaviest showers on Saturday.

Sunrise:
Sunset:

This evening forecast

Generally fine this evening with plenty of warm sunshine to end the day.

Sunrise:
Sunset:
Mountain hazards

Mountain weather hazards

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

hazard Strong Sunlight
Harmful UV levels from sunlight increase with altitude giving a greater risk of sunburn and eye damage, even on some overcast days. On breezy days, the cooling effect of wind on exposed skin may disguise any feeling of sunburn until it is too late. If there is snow cover, glare increases the effect of UV rays especially on the eyes. It is advisable to wear sun block, protective clothing such as a long-sleeved top and hat and have good quality eye protection.

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.

Mountain weather forecast

Mostly dry at first but an increasing chance of heavy showers.

00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
Weather
(at 600m)
Partly cloudy (night) Partly cloudy (night) Sunny intervals Sunny intervals Heavy shower (day) Heavy shower (day) Sunny intervals Sunny intervals
Chance of precipitation
(at 600m)
10% 10% 30% 30% 40% 60% 30% <05%

Wind direction and speed (mph)
Altitude above mean sea level
00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
600m SW
10
SW
10
SW
10
SW
12
SW
13
SW
14
W
10
W
7
300m SW
7
SW
6
SW
6
SW
8
W
8
SW
11
W
7
W
4
Valley SW
5
SW
5
SW
3
SW
7
W
8
SW
10
W
7
W
5
Wind gust (mph)
Altitude above mean sea level
00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
600m 16 15 14 17 19 21 15 11
300m 15 13 13 16 17 21 15 9
Valley 14 12 11 15 17 20 15 9

Altitude above mean sea level
00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
600m
10°
10°
11°
12°
13°
13°
10°
300m
11°
11°
12°
14°
15°
16°
16°
12°
Valley
11°
11°
12°
15°
16°
17°
16°
13°
Freezing Level
2,000m
2,000m
2,000m
2,300m
2,400m
2,200m
2,200m
2,200m

Altitude above mean sea level
00:00 03:00 06:00 09:00 12:00 15:00 18:00 21:00
600m
10°
11°
11°
300m
10°
10°
11°
13°
14°
14°
14°
12°
Valley
11°
10°
12°
14°
14°
15°
15°
12°

Additional weather information

Meteorologist's view

Some uncertainty still regarding the timing of the wettest period of weather on Saturday, but early morning and late afternoon onwards look like being the driest parts of the day. Whilst the chance of a thunderstorm is low, it's worth familiarising yourself with what to do if caught in a sudden thunderstorm on an exposed ridge or summit.

Weather

Generally dry through the early hours with clear spells and a small chance of an isolated shower in the south. Some early sunshine is likely after dawn but cloud amounts generally building with showers arriving from the west. These may be frequent for a few hours to give a more general spell of rain, especially in the west. Scattered heavy showers to begin the afternoon with a small chance of an isolated and brief thunderstorm. Showers easing by late afternoon to leave a mainly dry evening with increasing amounts of sunshine.

Chance of cloud-free hill tops

70%.

Low cloud and visibility

Periods of cloud above 700m during showers/rain, perhaps temporarily lowering to 600m during any more prolonged periods of precipitation. Generally very good visibility but occasionally moderate during rain/showers and poor/very poor in cloud. Locally very poor also in any heavier showers or thunderstorms.

Recent rainfall

Location: Neuadd (Near Pontsticill)
Altitude: 353m
Last 24 hoursLast 48 hoursLast 72 hours
0.2mm4.2mm4.2mm
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

Early morning mist and fog in the valleys will clear by mid-morning at the latest to leave a fine day with plenty of sunshine. Some fair weather cloud bubbling up through the morning but this will be above the highest summits from mid-morning onwards. Feeling much warmer in the strong sunshine and with very high UV levels.

Chance of cloud-free hill tops

80% becoming 100%.

Maximum wind speed expected

Southerly 15-20 mph.

Temperature

  • At 600m Plus 10 Celsius rising to plus 19 Celsius.
  • Valley Plus 7 Celsius rising to plus 24 Celsius.
  • Freezing level Well above the summits.

Low cloud and visibility

Shallow mist and fog patches in the valleys may lift to give ribbons of cloud around 400-600m for a time in the early to middle part of the morning. Thereafter all cloud will be above the summits. Locally very poor visibility first thing in any fog and cloud, otherwise very good visibility with distant hills and landmarks visible.

Mountain weather information

Mon 29 Jul

Sunrise:
Sunset:

Another dry, bright and warm day with sunny spells and areas of high-based cloud spreading across the National Park at times. Feeling warm with light southerly winds.

Tue 30 Jul

Sunrise:
Sunset:

Variable amounts of cloud but likely staying dry. Otherwise, sunny spells and gentle northerly winds and feeling very warm. Small chance of thundery showers overnight.

Wed 31 Jul

Sunrise:
Sunset:

Whilst details are still uncertain it will probably remain very warm and rather humid. There's the small risk of thundery showers but probably also some bright or sunny spells. Light easterly winds.

Updated at:

Summit specific forecast

Mountain summit forecast map

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