The highest day temperature in December 2025 was 42°F. The lowest night temperature was 16°F. The average values for day and night temperatures during December were 35.6°F и 35.4°F respectivly.

The average sea surface temperature in December 2025 for Turku was 37.5°F. The maximum and minimum values were 32.4°F and 41.4°F respectively.

Most of the days in December are gloomy but you can also expect sunny days.

Precipitation total in December for Turku is 2.1 in. It makes december one of the most rainy months of the year.

The average wind speed in December is 11.5 mph. This value is relatively stable throughout the year.

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 Turku in December is 1.7 hours.