Weather in Groton: December
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Average day temperature: | 40.9°F |
| Average night temperature: | 34.9°F | |
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Sea water temperature: | 48.4°F |
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Number of sunny days: | 13 days |
| Day length: | 9.2 - 9.4 hours | |
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Number of rainy days: | 3 days |
| Precipitation totals: | 1.4 in. | |
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forecast
| Groton |
temperature
| Groton |
Air temperature in December, °F
The highest day temperature during December of 2025 was 55°F. At the same time the lowest night temperature was 14°F. Daily and nightly averages during December were 37.4°F and 28.8°F.
Sea water temperature in Groton in December, °F
The average sea water temperature in December of 2025 was 46.2°F. The highest and lowest sea temperatures during the month were 50.7°F and 42.6°F.
Mostly all days in December are sunny but cloudy days are also possible.
Precipitation total in December, in.
Precipitation total value in Groton in December is 1.4 in. Other months of the year show relatively similar values.
The average wind speed value in December is 10.2 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: 5.3.
Best time for vacation in Groton
Groton on a weather map
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