The highest day temperature in September 2023 was 69°F. The lowest night temperature was 45°F. The average values for day and night temperatures during September were 63.5°F и 56.9°F respectivly.

The average sea surface temperature in September 2023 for Helsinki was 63.2°F. The maximum and minimum values were 59.8°F and 65.6°F respectively.

You can expect various weather conditions during September. Be ready for sunny, cloudy or even gloomy days.

Precipitation total in September for Helsinki is 1.9 in.

The average wind speed in September is 10.5 mph.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Helsinki in September is 6.9 hours.