Portishead sits near the bottom of UK towns for frosts
Sunny July days climb to about 21.2°C (70°F). December is the wettest month, April the driest. Only about 6 days a year reach 25°C, fewer than in 74% of UK towns. Warm coats and heating bills mark the months from November to April, when means dip under 10°C.
Met Office 1991–2020 averages for the town itself.
A year in Portishead at a glance
Each month’s typical high and low, in °C.
What a year in Portishead feels like
Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.
About 879 mm of rain a year
December is the wettest month and April the driest. About 27 days a year bring 10 mm (0.4 in) or more. 26th wettest of 49 Somerset towns of 2,500+.
Rain by month
Millimetres
19 air frosts and 6 days of 25°C a year
On about 19 nights a year the air drops below freezing; days that stay below freezing are rare. About 6 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 18 miles west of Portishead, 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 Portishead 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 Somerset 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 |
|---|---|---|---|
| Portishead | 21.2°C | 3.0°C | 879 mm |
| Avonmouth 3.5 mi | 21.8°C 0.6°C warmer | 3.0°C about the same | 799 mm |
| Pill 3.7 mi | 21.5°C about the same | 3.0°C about the same | 877 mm |
| Nailsea 3.7 mi | 20.9°C about the same | 2.9°C about the same | 965 mm |
| Clevedon 4.8 mi | 21.1°C about the same | 3.1°C about the same | 868 mm |
| Backwell 5.0 mi | 20.7°C about the same | 2.5°C 0.6°C colder | 985 mm |
| Long Ashton 5.9 mi | 21.5°C about the same | 2.6°C about the same | 909 mm |
Portishead 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 | 8.5°C 47°F | 3.0°C 37°F | 5.7°C | 94 mm 3.7 in |
| February | 8.9°C 48°F | 2.9°C 37°F | 5.9°C | 60 mm 2.4 in |
| March | 10.8°C 51°F | 4.1°C 39°F | 7.5°C | 60 mm 2.4 in |
| April | 13.6°C 57°F | 5.6°C 42°F | 9.6°C | 54 mm 2.1 in |
| May | 16.7°C 62°F | 8.5°C 47°F | 12.6°C | 57 mm 2.3 in |
| June | 19.3°C 67°F | 11.4°C 52°F | 15.4°C | 56 mm 2.2 in |
| July | 21.2°C 70°F | 13.3°C 56°F | 17.2°C | 68 mm 2.7 in |
| August | 21.2°C 70°F | 13.5°C 56°F | 17.5°C | 84 mm 3.3 in |
| September | 18.9°C 66°F | 11.5°C 53°F | 15.2°C | 64 mm 2.5 in |
| October | 15.2°C 59°F | 9.0°C 48°F | 12.2°C | 91 mm 3.6 in |
| November | 11.6°C 53°F | 5.9°C 43°F | 8.8°C | 95 mm 3.7 in |
| December | 9.2°C 48°F | 3.8°C 39°F | 6.5°C | 98 mm 3.8 in |
| Year | 14.6°C | 7.7°C | 11.2°C | 879 mm |
Where Portishead’s numbers come from
Averages over 30 years, not a forecast.
- Mean temperature, rain and day counts: HadUK-Grid 1991–2020 averages for the 2 Met Office 2 km grid squares whose centre lies inside Portishead’s built-up area.
- 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, 18 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 Portishead’s climate
How warm does Portishead get in summer?
August is the warmest month, with average highs of 21.2°C (70°F). About 6 days a year reach 25°C (77°F), fewer than 74% of UK towns.
How cold does Portishead get in winter?
February nights average 2.9°C (37°F). The air drops below freezing on about 19 nights a year, and about under 1 days a year stay below freezing all day.
How much rain does Portishead get?
About 879 mm (35 in) a year, more than 66% of UK towns. December is the wettest month (98 mm) and April the driest (54 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 Portishead. 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 Portishead →
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.