Photo: Chris Andrews · CC BY-SA 2.0Few UK towns get more rain than Llantrisant: 1,600 mm (63 in) a year
On a normal January night the air cools to about 2.0°C (36°F). Winters are mild: January nights here are milder than in 66% of UK towns. The gap between a January night and a July afternoon is 19°C. The outdoor season runs from June to September, with highs of 18–21°C.
Met Office 1991–2020 averages for the town itself.
A year in Llantrisant at a glance
Each month’s typical high and low, in °C.
What a year in Llantrisant feels like
Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.
About 1,600 mm of rain a year
December is the wettest month and May the driest. About 57 days a year bring 10 mm (0.4 in) or more. 20th wettest of 32 Mid Glamorgan towns of 2,500+.
Rain by month
Millimetres
41 air frosts and 10 days of 25°C a year
On about 41 nights a year the air drops below freezing, and on about 1 days it stays below freezing all day. About 10 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 8.8 miles south-east of Llantrisant, 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 Llantrisant 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 |
|---|---|---|---|
| Llantrisant | 21.0°C | 2.0°C | 1,600 mm |
| Talbot Green 0.6 mi | 21.3°C about the same | 2.2°C about the same | 1,342 mm |
| Pontyclun 1.0 mi | 21.3°C about the same | 2.2°C about the same | 1,342 mm |
| Beddau 1.5 mi | 21.0°C about the same | 2.0°C about the same | 1,590 mm |
| Creigiau 2.4 mi | 20.9°C about the same | 1.7°C about the same | 1,433 mm |
| Llanharry 2.8 mi | 21.0°C about the same | 2.0°C about the same | 1,445 mm |
| Church Village 2.9 mi | 21.0°C about the same | 2.1°C about the same | 1,599 mm |
Llantrisant 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 | 7.7°C 46°F | 2.0°C 36°F | 4.8°C | 169 mm 6.6 in |
| February | 8.1°C 46°F | 1.9°C 35°F | 4.9°C | 133 mm 5.2 in |
| March | 10.3°C 50°F | 3.0°C 37°F | 6.7°C | 114 mm 4.5 in |
| April | 13.4°C 56°F | 4.7°C 40°F | 9.1°C | 94 mm 3.7 in |
| May | 16.6°C 62°F | 7.4°C 45°F | 12.0°C | 93 mm 3.7 in |
| June | 19.3°C 67°F | 10.4°C 51°F | 14.8°C | 94 mm 3.7 in |
| July | 21.0°C 70°F | 12.2°C 54°F | 16.6°C | 107 mm 4.2 in |
| August | 20.5°C 69°F | 12.0°C 54°F | 16.3°C | 127 mm 5.0 in |
| September | 18.1°C 65°F | 9.9°C 50°F | 14.0°C | 121 mm 4.8 in |
| October | 14.2°C 58°F | 7.3°C 45°F | 10.8°C | 175 mm 6.9 in |
| November | 10.5°C 51°F | 4.4°C 40°F | 7.4°C | 176 mm 6.9 in |
| December | 8.1°C 47°F | 2.4°C 36°F | 5.2°C | 196 mm 7.7 in |
| Year | 14.0°C | 6.4°C | 10.2°C | 1,600 mm |
Where Llantrisant’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 Llantrisant’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, 8.8 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 Llantrisant’s climate
How warm does Llantrisant get in summer?
July is the warmest month, with average highs of 21.0°C (70°F). About 10 days a year reach 25°C (77°F), fewer than 55% of UK towns.
How cold does Llantrisant get in winter?
February nights average 1.9°C (35°F). The air drops below freezing on about 41 nights a year, and about 1 days a year stay below freezing all day.
How much rain does Llantrisant get?
About 1,600 mm (63 in) a year, more than 97% of UK towns. December is the wettest month (196 mm) and May the driest (93 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 Llantrisant. 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 Llantrisant →
Contains public sector information licensed under the Open Government Licence v3.0. Contains HM Land Registry data © Crown copyright and database right 2026. Contains OS data © Crown copyright and database right 2026 (ONS boundaries). Northern Ireland: Source: NISRA; contains Land & Property Services data and Ordnance Survey of Northern Ireland information, © Crown copyright, licensed under the Open Government Licence v3.0. Scotland: contains National Records of Scotland data, Registers of Scotland data and SEPA data, © Crown copyright / © SEPA 2025, licensed under the Open Government Licence v3.0.