December Weather in Charlestown, United States

Last updated: June 24, 2025

In December, the average temperature in Charlestown, United States hovers around 5°C (41°F), with a minimum of -10°C (15°F) and a maximum reaching 18°C (65°F). Expect about 98 mm (3.9 in) of precipitation spread over 9 days, and a high average humidity of 84%. Prepare for a chilly and damp month!

December Temperature in Charlestown

In December in Charlestown, the average temperature is 5°C (41°F). Maximums can reach 18°C (65°F), while minimums can drop as low as -10°C (15°F). Be prepared for a wide range of temperatures and pack accordingly for your travels.

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 5°C (41°F), with highs reaching up to 18°C (65°F) and lows dropping to around -10°C (15°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 98 mm (3.9 in) spread over a duration of 9 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 98 mm (3.9 inches) of precipitation spread over approximately 9 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

December Humidity in Charlestown

In Charlestown in December humidity is 84%. With an average temperature of 5°C (41°F), this humidity feels like a damp chill that seeps into your bones, making traveling uncomfortable as you navigate through the cold, heavy air that clings to your skin.

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 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Charlestown, you can check the information here.

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 3, which falls under the moderate 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	2°C (36°F)	60 mm (2.4 inches)	84%	moderate
February Weather	4°C (40°F)	97 mm (3.8 inches)	83%	moderate
March Weather	7°C (45°F)	97 mm (3.8 inches)	83%	high
April Weather	13°C (56°F)	100 mm (3.9 inches)	81%	very high
May Weather	18°C (65°F)	134 mm (5.3 inches)	78%	very high
June Weather	24°C (75°F)	96 mm (3.8 inches)	79%	very high
July Weather	27°C (80°F)	129 mm (5.1 inches)	74%	very high
August Weather	25°C (78°F)	133 mm (5.2 inches)	72%	very high
September Weather	22°C (72°F)	94 mm (3.7 inches)	75%	very high
October Weather	17°C (62°F)	104 mm (4.1 inches)	81%	high
November Weather	9°C (48°F)	81 mm (3.2 inches)	85%	moderate
December Weather	5°C (41°F)	98 mm (3.9 inches)	84%	moderate