Contents
Weather in September
Temperature
September brings a decrease in the average high-temperature, falling from August's enjoyable 19.8°C (67.6°F) to a moderate 14.6°C (58.3°F). Helsinki experiences an average temperature drop to a frosty 8.7°C (47.7°F) during September nights.Rainfall
In Helsinki, in September, during 14 rainfall days, 56mm (2.2") of precipitation is typically accumulated. In Helsinki, during the entire year, the rain falls for 182 days and collects up to 655mm (25.79") of precipitation.Snowfall
April through October are months without snowfall.Sea temperature
In Helsinki, the average seawater temperature in September is 14°C (57.2°F).Note: Dipping into 14°C (57.2°F) below 10°C (50°F) is possible with the right protection; absent that, anticipate cold shock and hampered breathing. Swimming momentarily at 13°C (55.4°F) can be jarring.
Daylight
In Helsinki, the average length of the day in September is 12h and 52min.On the first day of the month, sunrise is at 06:16 and sunset at 20:24. On the last day of September, in Helsinki, sunrise is at 07:24 and sunset at 18:55 EEST.
Sunshine
In September, the average sunshine in Helsinki is 5h.UV index
The average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for average individuals.Note: The average daily UV index of 3 in September transforms into the following instructions:
Take measures. Individuals with light skin might experience burns in under 30 minutes. When the Sun is at its strongest around midday, find shade and limit exposure. To cut down UV radiation exposure by about half, sport a wide-brim hat.
Frequently asked questions
What is the usual temperature for Helsinki in September?
How much does it rain in Helsinki in September?
When it does not snow in Helsinki?
What is the sea water temperature in September in Helsinki?
How many hours of daylight does Helsinki have in September?
When are sunrise and sunset in September in Helsinki?
How many hours of sunshine does Helsinki have in September?
How high is the UV index 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 5min
The month with the longest days is June (Average daylight: 18h and 48min).
The month with the shortest days is December (Average daylight: 6h and 0min).
- 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).
Helsinki, Finland
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