Photo: andy dolman · CC BY-SA 2.0Hardly any UK towns collect more rain than Tonna: 1,570 mm (62 in) a year
Midwinter brings lows of about 2.7°C (37°F). In January, nights here are milder than in 89% of UK towns. Of all months, December brings the most rain and April the least. Gritters and ice scrapers earn their keep on roughly 31 nights a year below 0°C.
Met Office 1991–2020 averages for the town itself.
A year in Tonna at a glance
Each month’s typical high and low, in °C.
What a year in Tonna feels like
Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.
About 1,570 mm of rain a year
December is the wettest month and April the driest. About 53 days a year bring 10 mm (0.4 in) or more. 7th wettest of 19 West Glamorgan towns of 2,500+.
Rain by month
Millimetres
31 air frosts and 8 days of 25°C a year
On about 31 nights a year the air drops below freezing, and on about under 1 days it stays below freezing all day. About 8 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 29 miles south-east of Tonna, 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 Tonna 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 West 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 |
|---|---|---|---|
| Tonna | 20.4°C | 2.7°C | 1,570 mm |
| Cilfrew 0.7 mi | 19.8°C 0.6°C cooler | 2.5°C about the same | 1,827 mm |
| Neath 1.6 mi | 20.3°C about the same | 3.2°C 0.5°C milder | 1,526 mm |
| Rhos 3.5 mi | 20.5°C about the same | 2.7°C about the same | 1,627 mm |
| Baglan 3.7 mi | 21.3°C 0.8°C warmer | 3.7°C 1.0°C milder | 1,283 mm |
| Cwmavon 4.0 mi | 20.6°C about the same | 2.7°C about the same | 1,569 mm |
| Alltwen 4.0 mi | 20.5°C about the same | 2.7°C about the same | 1,627 mm |
Tonna 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 | 8.1°C 47°F | 2.7°C 37°F | 5.4°C | 158 mm 6.2 in |
| February | 8.3°C 47°F | 2.5°C 37°F | 5.4°C | 115 mm 4.5 in |
| March | 10.3°C 50°F | 3.5°C 38°F | 6.9°C | 115 mm 4.5 in |
| April | 13.2°C 56°F | 5.1°C 41°F | 9.2°C | 84 mm 3.3 in |
| May | 16.3°C 61°F | 7.9°C 46°F | 12.2°C | 90 mm 3.6 in |
| June | 19.0°C 66°F | 10.6°C 51°F | 14.7°C | 103 mm 4.1 in |
| July | 20.4°C 69°F | 12.5°C 54°F | 16.4°C | 131 mm 5.2 in |
| August | 20.1°C 68°F | 12.5°C 54°F | 16.3°C | 138 mm 5.4 in |
| September | 17.9°C 64°F | 10.5°C 51°F | 14.3°C | 122 mm 4.8 in |
| October | 14.5°C 58°F | 8.1°C 47°F | 11.3°C | 170 mm 6.7 in |
| November | 10.9°C 52°F | 5.3°C 42°F | 8.1°C | 166 mm 6.5 in |
| December | 8.6°C 47°F | 3.1°C 38°F | 5.9°C | 177 mm 7.0 in |
| Year | 14.0°C | 7.0°C | 10.5°C | 1,570 mm |
Where Tonna’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 Tonna’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, 29 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 Tonna’s climate
How warm does Tonna get in summer?
July is the warmest month, with average highs of 20.4°C (69°F). About 8 days a year reach 25°C (77°F), fewer than 62% of UK towns.
How cold does Tonna get in winter?
February nights average 2.5°C (37°F). The air drops below freezing on about 31 nights a year, and about under 1 days a year stay below freezing all day.
How much rain does Tonna get?
About 1,570 mm (62 in) a year, more than 97% of UK towns. December is the wettest month (177 mm) and April the driest (84 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 Tonna. 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 Tonna →
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.