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Weather in September
Temperature
In September, the average high-temperature decreases from a comfortable 19.8°C (67.6°F) in August to a moderate 14.6°C (58.3°F). In September, in Helsinki, Finland, the average low-temperature is 8.7°C (47.7°F).Rainfall
In September, in Helsinki, the rain falls for 14 days. Throughout September, 56mm (2.2") of precipitation is accumulated. Throughout the year, there are 182 rainfall days, and 655mm (25.79") of precipitation is accumulated.Snowfall
In Helsinki, snow does not fall in April through October.Sea temperature
In Helsinki, the average seawater temperature in September is 14°C (57.2°F).Note: Swimming in 14°C (57.2°F) is considered dangerous. Unprotected immersion in temperatures below 10°C (50°F) causes quickly maximum intensity cold shock with hyperventilation.
Daylight
In September, the average length of the day is 12h and 52min.On the first day of the month, sunrise is at 06:14 and sunset at 20:26. On the last day of September, in Helsinki, sunrise is at 07:22 and sunset at 18:57 EEST.
Sunshine
In Helsinki, the average sunshine in September is 5h.UV index
In Helsinki, the average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the average person.Note: The average daily UV index of 3 in September transform into the following instructions:
Take precautions - Protection against sunburn is recommended. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
FAQ
What is the temperature in September in Helsinki?
How much does it rain in Helsinki in September?
When it does not snow in Helsinki?
How cold is the water in September in Helsinki?
What is the average length of the day in September in Helsinki?
When is the sunrise / sunset in September in Helsinki?
How many hours of sunshine does Helsinki have in September?
What is the UV index intensity in September in Helsinki?
Average temperature in September
Helsinki, Finland
- Average high temperature in September: 14.6°C
The warmest month (with the highest average high temperature) is July (21.5°C).
The month with the lowest average high temperature is February (-1.9°C).
- Average low temperature in September: 8.7°C
The month with the highest average low temperature is July (14.2°C).
The coldest month (with the lowest average low temperature) is February (-7.4°C).
Average rainfall in September
Helsinki, Finland
- Average rainfall in September: 56mm
The wettest month (with the highest rainfall) is August (80mm).
The driest month (with the least rainfall) is April (32mm).
Average rainfall days in September
Helsinki, Finland
- Average rainfall days in September: 14 days
The month with the highest number of rainy days is December (20 days).
The months with the least rainy days are April and May (11 days).
Average snowfall in September
Helsinki, Finland
- Average snowfall in September: 0mm
The month with the highest snowfall is February (230mm).
The months with the least snowfall are April, May, June, July, August, September and October (0mm).
Average sea temperature in September
Helsinki, Finland
- Average sea temperature in September: 14°C
The best month for swimming (with the highest average sea temperature) is August (16°C).
The coldest months (with the lowest average sea temperature) are February and March (1°C).
Average daylight in September /
Average sunshine in September
Helsinki, Finland
- Average daylight in September: 12h and 52min
The month with the longest days is June (Average daylight: 18h and 47min).
The month with the shortest days is December (Average daylight: 5h and 59min).
- Average sunshine in September: 5h and 0min
The month with the most sunshine is June (Average sunshine: 9h and 54min).
The month with the least sunshine is December (Average sunshine: 0h and 54min).
Average UV index in September
Helsinki, Finland
- Average UV index in September: 3
The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 0).
Weather forecast for your location
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