Helsinki Weather in September
In September, Helsinki averages a high of 15°C (59°F) and a low of 9°C (48°F), based on 55 years of historical weather data from HELSINKI RAUTATIENTORI.
15°C
Average high
59°F
9°C
Average low
48°F
26°C
Record high
78°F · 2024
-4°C
Record low
24°F · 1986
What to Expect in Helsinki in September
Typical September days in Helsinki reach 15°C (59°F) during the afternoon and cool to around 9°C (48°F) overnight. On average, measurable rain falls on about 51% of days this month. Over the past 55 years, September temperatures in Helsinki have ranged from a record high of 26°C (2024) down to a record low of -4°C (1986).
For a day-by-day look or other months, see the full Helsinki weather history.