Weather in Charlestown: December
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Average day temperature: | 41.9°F |
| Average night temperature: | 38.2°F | |
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Sea water temperature: | 48.7°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: | 2 days |
| Precipitation totals: | 1.3 in. | |
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forecast
| Charlestown |
temperature
| Charlestown |
Air temperature in December, °F
The highest day temperature during December of 2025 was 49°F. At the same time the lowest night temperature was 21°F. Daily and nightly averages during December were 38.7°F and 35.5°F.
Sea water temperature in Charlestown in December, °F
The average sea water temperature in December of 2025 was 46.5°F. The highest and lowest sea temperatures during the month were 51.1°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 Charlestown in December is 1.3 in. Other months of the year show relatively similar values.
The average wind speed value in December is 13.3 mph It makes December one of the most windy months 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: 5.2.
Best time for vacation in Charlestown
Charlestown on a weather map
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