Weather in Helsinki: December
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Average day temperature: | 33.7°F |
| Average night temperature: | 31.8°F | |
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Sea water temperature: | 38.7°F |
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Number of sunny days: | 3 days |
| Day length: | 5.8 - 6.4 hours | |
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Number of days with precipitation: | 4 days |
| Precipitation totals: | 2.1 in. | |
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forecast
| Helsinki |
temperature
| Helsinki |
Air temperature in December, °F
The highest day temperature during December of 2025 was 43°F. At the same time the lowest night temperature was 19°F. Daily and nightly averages during December were 36.1°F and 36.0°F.
Sea water temperature in Helsinki in December, °F
The average sea water temperature in December of 2025 was 39.5°F. The highest and lowest sea temperatures during the month were 41.9°F and 36.7°F.
Mostly all days in December are cloudy but sunny and partly cloudy days are also possible.
Precipitation total in December, in.
Precipitation total value in Helsinki in December is 2.1 in. Other months of the year show relatively similar values.
The average wind speed value in December is 11.4 mph It makes December most windy month of the year.
This chart shows average number of hours during the day when sunlight can reach the ground. It depends on day length and cloudiness during the day. The average number of sunny hours in December is: 1.5.
Best time for vacation in Helsinki
Helsinki on a weather map
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