The climate in Portsmouth during September can be summarized as hot, humid and very wet.
September is in the fall / autumn in Portsmouth and is typically the 3rd warmest month of the year. Daytime maximum temperatures average around a steamy 31°C (88°F), whilst at night 24°C (74°F) is normal.
|Daytime temperature||31°C 87.7°F|
|Nightly temperature||23.5°C 74.2°F|
|Average temperature||27.2°C 81°F|
|Daily sunshine||7.6 hrs|
|Avg rainfall||269 mm 10.6 ins|
|Rainy days||22 days|
|Sea temperature||29°C 84.2°F|
|Windspeed||14.8kph 9 mph|
On average September is the 3rd wettest month of the year in Portsmouth with around 269mm 10.6 inches of rain making it a very wet time to visit. This rainfall is typically spread over 22 days, although this may vary considerably.
On the flip side this corresponds to an average of 7.6 hours of sunshine per day.
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 September 2023.
|Hottest month:||July||30.6°C 87.1°F|
|Driest month:||February||95mm 3.7ins|
|Coldest month:||February||28.3°C 82.9°F|
|Wettest month:||November||301mm 11.9ins|