Turku, where it's located

The climate of Turku is Baltic, that is, moderately continental, with cold winters, during which the average temperature is a few degrees below freezing, and mild to pleasantly warm summers.
The city is located in the south-west of Finland. The white nights occur from 11 May to 3 August.
The average temperature of the coldest month (February) is of -5.2 °C (23 °F), that of the warmest month (July) is of 17.5 °C (63 °F). In January 1987, it fell to -35 °C (-31 °F), while in summer, it reached 32 °C (89.5 °F) in July 2010. Here are the average temperatures.
Turku - Average temperatures
Min (°C)-7-8-5059131273-2-6
Max (°C)-2-2291620222015930
Min (°F)191823324148555445372821
Max (°F)282836486168726859483732

Precipitation amounts to 725 millimeters (28.5 inches) per year: so, it is at an intermediate level. It ranges from 30 mm (1.2 in) in the driest month (April) to 80 mm (3.1 in) in the wettest ones (July, August, October). Here is the average precipitation.
Turku - Average precipitation

On average, there are around 1,840 sunshine hours per year. Here are the average sunshine hours per day.
Turku - Sunshine

The sea temperature ranges between 1 °C (34 °F) and 17 °C (63 °F). So, it never becomes warm for swimming. Here are the average sea temperatures.
Turku - Sea temperature
Temp (°C)32136111617151185
Temp (°F)373634374352616359524641


Best Time

The best time to visit Turku is the summer, from June to August, since it is the mildest season. However, you must take into account some rainy days and a bit of cold at night.