December Weather in Charlestown, United States

Last updated: June 24, 2025

In December, the average temperature in Charlestown, United States hovers around -3°C (27°F), with extremes that can plunge to a chilling -25°C (-13°F) or rise to a mild 14°C (58°F). Expect about 104 mm (4.1 in) of precipitation spread over 10 days, and stay prepared for high humidity levels at an average of 84%.

December Temperature in Charlestown

In December in Charlestown, the average temperature is -3°C (27°F), with maximums reaching up to 14°C (58°F) and minimums dropping as low as -25°C (-13°F). Travelers should be prepared for a wide range of temperatures and pack accordingly.

December Weather in Charlestown: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Charlestown, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Charlestown, December typically has an average temperature of -3°C (27°F), with highs reaching up to 14°C (58°F) and lows dropping to around -25°C (-13°F).

Data source: Temperature data for Charlestown generated using information from the Copernicus Climate Change Service.

December Precipitation in Charlestown

In Charlestown in December, the precipitation amount is 104 mm (4.1 in) over a period of 10 days.

December Precipitation Trends in Charlestown

The chart displays monthly precipitation patterns in Charlestown, with values for each month alongside December’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December’s conditions compare to those of other months. In Charlestown, December typically receives around 104 mm (4.1 inches) of precipitation spread over approximately 10 days.

Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

December Humidity in Charlestown

In Charlestown in December humidity is 84%. With an average temperature of -3°C (27°F), this humidity feels like a heavy blanket that wraps around you, making travel uncomfortable and your breath visible in the cold air.

December Average Humidity in Charlestown

This chart illustrates the average monthly humidity levels in Charlestown, with December’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In December, average humidity in Charlestown is approximately 84%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Charlestown

In Charlestown in December, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Charlestown, you can visit Hourly UV Index in Charlestown.

Maximum UV Index Levels in Charlestown for December

The chart shows the monthly maximum UV Index (UVI) for Charlestown in December, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In December, the maximum UV index in Charlestown typically reaches 2, which falls under the low exposure category.

Data source: Charlestown December UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How December Weather in Charlestown Compares to Other Months

Weather in Charlestown varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Charlestown, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Charlestown, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-5°C (23°F)	72 mm (2.9 inches)	89%	moderate
February Weather	-4°C (26°F)	85 mm (3.3 inches)	88%	moderate
March Weather	0°C (32°F)	73 mm (2.9 inches)	86%	high
April Weather	7°C (44°F)	122 mm (4.8 inches)	84%	very high
May Weather	13°C (56°F)	85 mm (3.3 inches)	76%	very high
June Weather	19°C (66°F)	90 mm (3.5 inches)	72%	very high
July Weather	22°C (71°F)	126 mm (5.0 inches)	66%	very high
August Weather	20°C (69°F)	92 mm (3.6 inches)	64%	very high
September Weather	17°C (62°F)	79 mm (3.1 inches)	72%	high
October Weather	10°C (51°F)	142 mm (5.6 inches)	81%	high
November Weather	2°C (36°F)	101 mm (4.0 inches)	87%	moderate
December Weather	-3°C (27°F)	104 mm (4.1 inches)	84%	low