Few UK towns get more rain than Treherbert: 2,687 mm (106 in) a year
Sunny July days climb to about 18.0°C (64°F). December is the wettest month, May the driest. Of the 32 Mid Glamorgan towns, it has the coolest July afternoons. The heating season runs October to May: each of those months averages under 10°C.
Met Office 1991–2020 averages for the town itself.
A year in Treherbert at a glance
Each month’s typical high and low, in °C.
What a year in Treherbert feels like
Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.
About 2,687 mm of rain a year
December is the wettest month and May the driest. About 88 days a year bring 10 mm (0.4 in) or more. The wettest of 32 Mid Glamorgan towns of 2,500+.
Rain by month
Millimetres
A frosty town: 54 air frosts and 3 days of 25°C a year
On about 54 nights a year the air drops below freezing, and on about 3 days it stays below freezing all day. About 3 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 20 miles south-east of Treherbert, 9 m (30 ft) above sea level. It is the nearest of the 37 long-running stations the Met Office publishes in full.
| 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 Treherbert 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 Mid Glamorgan 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 |
|---|---|---|---|
| Treherbert | 18.0°C | 1.2°C | 2,687 mm |
| Treorchy 1.6 mi | 18.4°C about the same | 1.6°C about the same | 2,503 mm |
| Maerdy 2.5 mi | 19.5°C 1.6°C warmer | 1.0°C about the same | 2,411 mm |
| Rhondda 3.5 mi | 19.5°C 1.6°C warmer | 1.7°C about the same | 2,402 mm |
| Nant-y-moel 3.7 mi | 18.4°C about the same | 1.5°C about the same | 2,478 mm |
| Ferndale 4.1 mi | 19.5°C 1.6°C warmer | 1.2°C about the same | 2,382 mm |
| Blaengarw 4.1 mi | 18.4°C about the same | 1.5°C about the same | 2,483 mm |
Treherbert 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 | 6.4°C 44°F | 1.2°C 34°F | 3.8°C | 312 mm 12.3 in |
| February | 6.0°C 43°F | 0.5°C 33°F | 3.2°C | 228 mm 9.0 in |
| March | 8.1°C 46°F | 1.6°C 35°F | 4.9°C | 196 mm 7.7 in |
| April | 10.6°C 51°F | 2.8°C 37°F | 6.8°C | 148 mm 5.8 in |
| May | 14.0°C 57°F | 5.7°C 42°F | 9.8°C | 141 mm 5.6 in |
| June | 16.2°C 61°F | 8.0°C 46°F | 12.0°C | 152 mm 6.0 in |
| July | 18.0°C 64°F | 10.1°C 50°F | 14.1°C | 178 mm 7.0 in |
| August | 17.5°C 64°F | 10.1°C 50°F | 13.9°C | 206 mm 8.1 in |
| September | 15.5°C 60°F | 8.3°C 47°F | 12.0°C | 205 mm 8.1 in |
| October | 11.9°C 53°F | 5.7°C 42°F | 8.8°C | 295 mm 11.6 in |
| November | 8.5°C 47°F | 3.3°C 38°F | 5.8°C | 294 mm 11.6 in |
| December | 6.5°C 44°F | 1.3°C 34°F | 3.9°C | 332 mm 13.1 in |
| Year | 11.6°C | 4.9°C | 8.2°C | 2,687 mm |
Where Treherbert’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 Treherbert’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, 20 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 Treherbert’s climate
How warm does Treherbert get in summer?
July is the warmest month, with average highs of 18.0°C (64°F). About 3 days a year reach 25°C (77°F), fewer than 85% of UK towns.
How cold does Treherbert get in winter?
February nights average 0.5°C (33°F). The air drops below freezing on about 54 nights a year, and about 3 days a year stay below freezing all day.
How much rain does Treherbert get?
About 2,687 mm (106 in) a year, more than almost every UK town. December is the wettest month (332 mm) and May the driest (141 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 Treherbert. 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 Treherbert →
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