Photo: Mick Lobb · CC BY-SA 2.0Hardly any UK towns collect more rain than Llanharry: 1,445 mm (57 in) a year
High summer brings afternoon highs near 21.0°C (70°F). Its January nights stay gentler than in 69% of UK towns. Temperatures cover 19°C across the year, low to high. Garden chairs stay out from June to September, the months with highs of 18–21°C.
Met Office 1991–2020 averages for the town itself.
A year in Llanharry at a glance
Each month’s typical high and low, in °C.
What a year in Llanharry feels like
Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.
About 1,445 mm of rain a year
November is the wettest month and April the driest. About 49 days a year bring 10 mm (0.4 in) or more. 27th 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 under 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 10 miles east of Llanharry, 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 Llanharry 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 |
|---|---|---|---|
| Llanharry | 21.0°C | 2.0°C | 1,445 mm |
| Pontyclun 1.9 mi | 21.3°C about the same | 2.2°C about the same | 1,342 mm |
| Llanharan and Brynna 2.0 mi | 20.7°C about the same | 2.1°C about the same | 1,448 mm |
| Talbot Green 2.2 mi | 21.3°C about the same | 2.2°C about the same | 1,342 mm |
| Llantrisant 2.8 mi | 21.0°C about the same | 2.0°C about the same | 1,600 mm |
| Pencoed 3.5 mi | 20.4°C 0.5°C cooler | 2.3°C about the same | 1,574 mm |
| Cowbridge 3.7 mi | 20.8°C about the same | 2.3°C about the same | 1,175 mm |
Llanharry 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 | 7.8°C 46°F | 2.0°C 36°F | 4.9°C | 143 mm 5.6 in |
| February | 8.3°C 47°F | 2.1°C 36°F | 5.2°C | 113 mm 4.5 in |
| March | 10.6°C 51°F | 3.3°C 38°F | 7.0°C | 101 mm 4.0 in |
| April | 13.6°C 56°F | 4.8°C 41°F | 9.2°C | 83 mm 3.3 in |
| May | 16.8°C 62°F | 7.6°C 46°F | 12.2°C | 88 mm 3.4 in |
| June | 19.3°C 67°F | 10.4°C 51°F | 14.8°C | 89 mm 3.5 in |
| July | 21.0°C 70°F | 12.2°C 54°F | 16.6°C | 106 mm 4.2 in |
| August | 20.6°C 69°F | 12.1°C 54°F | 16.5°C | 129 mm 5.1 in |
| September | 18.3°C 65°F | 10.1°C 50°F | 14.2°C | 115 mm 4.5 in |
| October | 14.6°C 58°F | 7.6°C 46°F | 11.1°C | 154 mm 6.1 in |
| November | 10.9°C 52°F | 4.8°C 41°F | 7.8°C | 165 mm 6.5 in |
| December | 8.4°C 47°F | 2.7°C 37°F | 5.5°C | 161 mm 6.3 in |
| Year | 14.2°C | 6.6°C | 10.4°C | 1,445 mm |
Where Llanharry’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 Llanharry’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, 10 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 Llanharry’s climate
How warm does Llanharry 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 Llanharry get in winter?
January nights average 2.0°C (36°F). The air drops below freezing on about 41 nights a year, and about under 1 days a year stay below freezing all day.
How much rain does Llanharry get?
About 1,445 mm (57 in) a year, more than 95% of UK towns. November is the wettest month (165 mm) and April the driest (83 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 Llanharry. 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 Llanharry →
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.