Ristinummi Weather in September

What's the weather like in Ristinummi (Province of Western Finland) in September 2025?

The climate in Ristinummi during September can be summarized as cool and reasonably dry.

September is in the fall / autumn in Ristinummi and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a cool 13°C (55°F), whilst at night 6°C (42°F) is normal.

Ristinummi weather averages (imperial / metric)
Daytime temperature 12.8°C 55°F
Nightly temperature 5.8°C 42.4°F
Average temperature 9.3°C 48.7°F
Daily sunshine 3.9 hrs
Avg rainfall 61 mm 2.4 ins
Rainy days 17 days
Sea temperature 12.3°C 54.2°F
Humidity 84%
Windspeed 16.2kph 10 mph

On average September is the 2nd wettest month of the year in Ristinummi with around 61mm 2.4 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 17 days, although this may vary considerably.

On the flip side this corresponds to an average of 3.9 hours of sunshine per day.

September temperatures in Ristinummi

Ristinummi average temperature in September

September rainfall

Ristinummi average rain in September

September hourly sunshine

Ristinummi average rain in September

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 Ristinummi in September 2025.

Other monthly averages

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UV index Best time to go?

Ristinummi weather stats

Ristinummi weather statistics
Hottest month: July 19.8°C 67.6°F
Driest month: February 23mm 0.9ins
Sunniest month: June 0hrs
Coldest month: January -4.9°C 23.2°F
Wettest month: August 64mm 2.5ins
Map showing location of Ristinummi (63.09192, 21.72297) Ristinummi map pin © Google

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