Weather in Turku in September 2025
Average weather
Average temperature in Turku in September
The expected average maximum temperature in September is +18°C with a maximum of +22°C and a minimum of +3°C.
The average maximum temperature goes down 11% by the end of the month, compared with the beginning of the month, from +18°C to +16°C.
Is Turku warm or cold in September?
Turku is typically mild in September.
Maximum temperatures go down compared to the previous month from +20°C to +15°C. The minimum temperature also goes down from +12°C to +8°C.
Pack a light jacket as it will be warm in the day and cool in the evenings.
Take a look at how September is compared to other months in Turku:
Water temperature in Turku in September
Water in Turku in September is Cold. It varies from +4°C to +19°C, with an average of +11°C. This is almost similar to the air temperature, which averages +15°C.
The water temperature in September is one of the warmest of the entire year:
Can you swim in Turku in September?
Climate in Turku in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +20°C | +15°C | +9°C | ||||
| Min. temperature | ||||||
| +3°C | -3°C | -12°C | ||||
| Max. temperature | ||||||
| +31°C | +24°C | +17°C | ||||
| Rainfall | ||||||
| 75 mm | 56 mm | 60 mm | ||||
| Wind | ||||||
| 3 m/s | 3 m/s | 4 m/s | ||||
| Avg. water temperature | ||||||
| +14°C | +11°C | +8°C | ||||
| Humidity | ||||||
| 77% | 82% | 85% | ||||
| Air pressure | ||||||
| 1011 HPa | 1011 HPa | 1011 HPa | ||||
| Sunny days | ||||||
| 7 | 6 | 4 | ||||
| Cloudy days | ||||||
| 6 | 9 | 11 | ||||
| Rainy days | ||||||
| 17 | 15 | 15 | ||||
| Snowy days | ||||||
| 0 | 0 | 1 | ||||
September weather is still as ok as in August. It’s getting colder in September. From +20°C in the day, the average maximum temperature lowers to +15°C. As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 75 mm to 56 mm. Humidity rises from 77% to 82%. The average wind speed doesn’t change much during September, staying around 3 m/s. The days becoming less sunny, going from 7 sunny days in August to 6 in September.
October brings much the same weather, it remains ok.
Wind
The average wind speed is 3 m/s getting up to 6 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Turku is gradually increasing during September, going from 2 m/s to 4 m/s over the course of the month.
Rain
How was the weather last September in Turku?
Climate Change over Years
The climate in Turku in September has not changed much over the last 43 years.
The average temperature was the lowest in 1987 (+6°C) and the highest in 2020 (+11°C). The driest year was 2003 with only 300 mm of rainfall, and the wettest year was 2020 with 615 mm.
FAQ
Is September a good time to visit Turku?
Can you sunbathe in Turku in September?
Can you swim in Turku in September?
Is Turku rainy in September?
Is it sunny in Turku in September?
Other cities in Finland
Monthly weather in Turku
Source of the data
For this page, we’ve looked at the typical weather in Turku, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.