Portsmouth Weather in December
What's the weather like in Portsmouth (Saint John) in December 2025?
The climate in Portsmouth during December can be summarized as hot, humid and very wet.
December is in the winter in Portsmouth and is typically the 4th coldest month of the year. Daytime maximum temperatures average around a steamy 29°C (84°F), whilst at night 22°C (71°F) is normal.
| Daytime temperature | 29.1°C 84.4°F |
|---|---|
| Nightly temperature | 21.7°C 71.1°F |
| Average temperature | 25.4°C 77.7°F |
| Daily sunshine | 6.8 hrs |
| Avg rainfall | 201 mm 7.9 ins |
| Rainy days | 18 days |
| Sea temperature | 27.6°C 81.7°F |
| Humidity | 80% |
| Windspeed | 16.6kph 10 mph |
On average December is the 5th wettest month of the year in Portsmouth with around 201mm 7.9 inches of rain making it a very wet time to visit. This rainfall is typically spread over 18 days, although this may vary considerably.
On the flip side this corresponds to an average of 6.8 hours of sunshine per day.
December temperatures in Portsmouth
December rainfall
December hourly sunshine
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Portsmouth in December 2025.
Other monthly averages
Best places to visit in December
Portsmouth weather stats
| Hottest month: | July | 30.6°C 87.1°F |
|---|---|---|
| Driest month: | February | 95mm 3.7ins |
| Sunniest month: | April | 8.6hrs |
| Coldest month: | February | 28.3°C 82.9°F |
| Wettest month: | November | 301mm 11.9ins |
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