January in Portesham stays gentler than in 87% of UK towns
High summer brings afternoon highs near 21.1°C (70°F). It is a wet place: more rain falls here than on 78% of UK towns. Rain peaks in November and eases off in May. Keep the boiler serviced for the months from November to April, which average under 10°C.
Met Office 1991–2020 averages for the town itself.
A year in Portesham at a glance
Each month’s typical high and low, in °C.
What a year in Portesham feels like
Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.
About 996 mm of rain a year
November is the wettest month and May the driest. About 33 days a year bring 10 mm (0.4 in) or more.
Rain by month
Millimetres
Sunshine by month
Hours of bright sunshine at Yeovilton
30 air frosts and 5 days of 25°C a year
On about 30 nights a year the air drops below freezing, and on about under 1 days it stays below freezing all day. About 5 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 Yeovilton
Yeovilton is 23 miles north of Portesham, 20 m (66 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 | Sun (hours) |
|---|---|---|---|---|---|
| January | 8.6°C | 2.0°C | 70 mm | 10.0 | 58 |
| February | 9.0°C | 1.8°C | 51 mm | 9.7 | 77 |
| March | 11.2°C | 3.0°C | 49 mm | 7.6 | 114 |
| April | 13.9°C | 4.5°C | 52 mm | 3.8 | 163 |
| May | 17.1°C | 7.4°C | 47 mm | 0.5 | 191 |
| June | 19.9°C | 10.3°C | 58 mm | 0.0 | 188 |
| July | 21.9°C | 12.2°C | 50 mm | 0.0 | 192 |
| August | 21.6°C | 12.2°C | 61 mm | 0.0 | 175 |
| September | 19.2°C | 10.0°C | 53 mm | 0.0 | 142 |
| October | 15.3°C | 7.6°C | 81 mm | 1.8 | 104 |
| November | 11.5°C | 4.4°C | 80 mm | 5.5 | 69 |
| December | 9.0°C | 2.3°C | 77 mm | 10.3 | 52 |
| Year | 14.9°C | 6.5°C | 728 mm | 49 | 1,524 |
Met Office historic station data, Yeovilton, 1991–2020 months averaged (a month needs 20 of the 30 years; estimated values counted, missing months left out). Sunshine: Kipp & Zonen recorder.
How Portesham 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 Dorset 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 |
|---|---|---|---|
| Portesham | 21.1°C | 2.6°C | 996 mm |
| Chickerell 4.3 mi | 21.7°C 0.5°C warmer | 3.5°C 0.9°C milder | 784 mm |
| Weymouth 5.6 mi | 22.2°C 1.1°C warmer | 3.5°C 0.9°C milder | 855 mm |
| Dorchester 5.9 mi | 21.7°C 0.5°C warmer | 2.4°C about the same | 1,089 mm |
| Charminster 6.3 mi | 21.3°C about the same | 2.3°C about the same | 1,131 mm |
| Charlton Down 7.3 mi | 21.3°C about the same | 2.2°C about the same | 1,137 mm |
| Maiden Newton 7.4 mi | 21.1°C about the same | 1.4°C 1.2°C colder | 1,084 mm |
Portesham 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 | 8.4°C 47°F | 2.6°C 37°F | 5.4°C | 107 mm 4.2 in |
| February | 8.6°C 47°F | 2.2°C 36°F | 5.3°C | 73 mm 2.9 in |
| March | 10.7°C 51°F | 3.2°C 38°F | 6.9°C | 70 mm 2.8 in |
| April | 13.6°C 56°F | 4.6°C 40°F | 9.0°C | 67 mm 2.6 in |
| May | 16.7°C 62°F | 7.2°C 45°F | 11.9°C | 58 mm 2.3 in |
| June | 19.2°C 67°F | 9.9°C 50°F | 14.4°C | 58 mm 2.3 in |
| July | 21.1°C 70°F | 11.8°C 53°F | 16.5°C | 61 mm 2.4 in |
| August | 21.1°C 70°F | 12.0°C 54°F | 16.5°C | 77 mm 3.0 in |
| September | 18.9°C 66°F | 10.2°C 50°F | 14.5°C | 74 mm 2.9 in |
| October | 15.3°C 60°F | 8.0°C 46°F | 11.6°C | 114 mm 4.5 in |
| November | 11.6°C 53°F | 5.1°C 41°F | 8.3°C | 122 mm 4.8 in |
| December | 9.0°C 48°F | 3.0°C 37°F | 5.9°C | 116 mm 4.6 in |
| Year | 14.5°C | 6.7°C | 10.5°C | 996 mm |
Where Portesham’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 Portesham’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 Yeovilton, 23 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 Portesham’s climate
How warm does Portesham get in summer?
August is the warmest month, with average highs of 21.1°C (70°F). About 5 days a year reach 25°C (77°F), fewer than 75% of UK towns.
How cold does Portesham get in winter?
February nights average 2.2°C (36°F). The air drops below freezing on about 30 nights a year, and about under 1 days a year stay below freezing all day.
How much rain does Portesham get?
About 996 mm (39 in) a year, more than 78% of UK towns. November is the wettest month (122 mm) and May the driest (58 mm).
How sunny is it?
The nearest Met Office station with a sunshine record, Yeovilton (23 miles away), averages 1,524 hours of bright sunshine a year. Sunshine isn’t on the town grid, so this is the station’s figure.
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 Portesham. 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 Portesham →
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.