Cwm-twrch Uchaf is among the wettest of UK towns: 1,997 mm (79 in) of rain a year
Expect July afternoons of about 20.1°C (68°F). Seasons differ by 18°C, from the coldest nights to the warmest afternoons. In January, nights here are milder than in 74% of UK towns. Picnics, hikes and garden evenings come into their own from June to September, with highs of 17–20°C.
Met Office 1991–2020 averages for the town itself.
A year in Cwm-twrch Uchaf at a glance
Each month’s typical high and low, in °C.
What a year in Cwm-twrch Uchaf feels like
Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.
About 1,997 mm of rain a year
December is the wettest month and May the driest. About 67 days a year bring 10 mm (0.4 in) or more.
Rain by month
Millimetres
38 air frosts and 6 days of 25°C a year
On about 38 nights a year the air drops below freezing, and on about under 1 days it stays below freezing all day. About 6 days a year reach 25°C (77°F).
Day counts are 1991–2020 averages from the Met Office’s 2 km grid. The Met Office calls a day of 25°C or more a summer day and a night below 0°C an air frost; ground frosts, on grass, come more often.
The Met Office station at Cardiff Bute Park
Cardiff Bute Park is 34 miles south-east of Cwm-twrch Uchaf, 9 m (30 ft) above sea level. It is the nearest of the 37 long-running stations the Met Office publishes in full; at that distance read it for sunshine and the station’s own record, not as the town’s figures.
| Month | High | Low | Rain | Air frosts |
|---|---|---|---|---|
| January | 8.6°C | 2.5°C | 127 mm | 8.1 |
| February | 9.1°C | 2.5°C | 93 mm | 7.5 |
| March | 11.3°C | 3.9°C | 85 mm | 3.9 |
| April | 14.4°C | 5.7°C | 72 mm | 1.4 |
| May | 17.4°C | 8.5°C | 78 mm | 0.0 |
| June | 20.1°C | 11.3°C | 73 mm | 0.0 |
| July | 21.8°C | 13.1°C | 84 mm | 0.0 |
| August | 21.4°C | 12.9°C | 105 mm | 0.0 |
| September | 19.1°C | 10.7°C | 87 mm | 0.0 |
| October | 15.2°C | 8.0°C | 128 mm | 1.0 |
| November | 11.6°C | 4.9°C | 131 mm | 3.7 |
| December | 9.1°C | 2.9°C | 140 mm | 8.3 |
| Year | 14.9°C | 7.2°C | 1,201 mm | 34 |
Met Office historic station data, Cardiff Bute Park, 1991–2020 months averaged (a month needs 20 of the 30 years; estimated values counted, missing months left out). Sunshine: Campbell-Stokes recorder.
How Cwm-twrch Uchaf compares
Against the 2,537 towns and cities of 2,500 or more across the UK, each with its own Met Office averages, and its place among Powys towns that size.
Nearby towns’ climate
The nearest towns of 1,000+ within 12 miles: a hill, a valley or the sea can make a real difference over a few miles.
| Town | July high | January low | Rain a year |
|---|---|---|---|
| Cwm-twrch Uchaf | 20.1°C | 2.2°C | 1,997 mm |
| Cwmllynfell and Ystradowen 1.1 mi | 20.1°C about the same | 2.2°C about the same | 1,997 mm |
| Ystalyfera 1.8 mi | 20.3°C about the same | 2.2°C about the same | 1,920 mm |
| Ystradgynlais 2.2 mi | 20.3°C about the same | 2.2°C about the same | 1,923 mm |
| Gwaun-Cae-Gurwen 3.2 mi | 19.9°C about the same | 2.1°C about the same | 1,720 mm |
| Brynamman 3.3 mi | 19.9°C about the same | 2.1°C about the same | 1,716 mm |
| Seven Sisters 4.2 mi | 20.2°C about the same | 1.9°C about the same | 1,921 mm |
Cwm-twrch Uchaf weather by month
Average daily high and low, mean temperature and rain, 1991–2020, for the town itself (the Met Office’s HadUK-Grid).
| Month | High | Low | Mean | Rain |
|---|---|---|---|---|
| January | 7.5°C 46°F | 2.2°C 36°F | 4.8°C | 210 mm 8.3 in |
| February | 7.9°C 46°F | 2.0°C 36°F | 4.9°C | 172 mm 6.8 in |
| March | 9.8°C 50°F | 3.1°C 37°F | 6.4°C | 151 mm 5.9 in |
| April | 12.9°C 55°F | 4.9°C 41°F | 8.9°C | 123 mm 4.8 in |
| May | 16.1°C 61°F | 7.6°C 46°F | 11.8°C | 114 mm 4.5 in |
| June | 18.5°C 65°F | 10.4°C 51°F | 14.4°C | 118 mm 4.6 in |
| July | 20.1°C 68°F | 12.2°C 54°F | 16.1°C | 136 mm 5.4 in |
| August | 19.7°C 68°F | 12.1°C 54°F | 15.9°C | 155 mm 6.1 in |
| September | 17.5°C 63°F | 10.0°C 50°F | 13.7°C | 163 mm 6.4 in |
| October | 13.9°C 57°F | 7.6°C 46°F | 10.7°C | 212 mm 8.3 in |
| November | 10.3°C 51°F | 4.5°C 40°F | 7.4°C | 214 mm 8.4 in |
| December | 8.0°C 46°F | 2.5°C 37°F | 5.2°C | 229 mm 9.0 in |
| Year | 13.5°C | 6.6°C | 10.0°C | 1,997 mm |
Where Cwm-twrch Uchaf’s numbers come from
Averages over 30 years, not a forecast.
- Mean temperature, rain and day counts: HadUK-Grid 1991–2020 averages for the Met Office 2 km grid square nearest Cwm-twrch Uchaf’s centre (the town is smaller than one square).
- Highs and lows: the Met Office publishes average daily maxima and minima on its 12 km grid; each is moved by the difference between the town’s 2 km mean temperature and the 12 km square’s, which carries the town’s own height and setting over.
- Weather station and sunshine: Met Office historic station data for Cardiff Bute Park, 34 miles away, months of 1991–2020 averaged.
- Comparisons: every town and city of 2,500 or more across the UK, all four nations, read the same way.
Met Office HadUK-Grid · Met Office Climate Data Portal · Historic station data. Open Government Licence v3.0.
Questions about Cwm-twrch Uchaf’s climate
How warm does Cwm-twrch Uchaf get in summer?
July is the warmest month, with average highs of 20.1°C (68°F). About 6 days a year reach 25°C (77°F), fewer than 71% of UK towns.
How cold does Cwm-twrch Uchaf get in winter?
February nights average 2.0°C (36°F). The air drops below freezing on about 38 nights a year, and about under 1 days a year stay below freezing all day.
How much rain does Cwm-twrch Uchaf get?
About 1,997 mm (79 in) a year, more than almost every UK town. December is the wettest month (229 mm) and May the driest (114 mm).
Where do these figures come from?
The Met Office’s HadUK-Grid 1991–2020 averages, which turn thousands of weather stations into a map of the UK in 2 km squares; the page reads the squares inside Cwm-twrch Uchaf. They are 30-year averages, not a forecast.
Contains Met Office data © Crown copyright 2026, Open Government Licence v3.0. HadUK-Grid 1991–2020 averages via the Met Office Climate Data Portal; station averages from Met Office historic station data. Today’s forecast for Cwm-twrch Uchaf →
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