The climate in Helsinki during September can be summarized as mild and reasonably dry.
September is in the fall / autumn in Helsinki and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a cool 14°C (57°F), whilst at night 8°C (47°F) is normal.
|Daytime temperature||13.8°C 56.8°F|
|Nightly temperature||8.2°C 46.8°F|
|Average temperature||11°C 51.8°F|
|Daily sunshine||4.4 hrs|
|Avg rainfall||64 mm 2.5 ins|
|Rainy days||16 days|
|Sea temperature||13.9°C 57°F|
|Windspeed||18kph 11 mph|
On average September is the 2nd wettest month of the year in Helsinki with around 64mm 2.5 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 16 days, although this may vary considerably.
On the flip side this corresponds to an average of 4.4 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 Helsinki in September 2022.
|Hottest month:||July||19.5°C 67.1°F|
|Driest month:||February||25mm 1ins|
|Coldest month:||February||-2.7°C 27.1°F|
|Wettest month:||August||75mm 3ins|