December Weather in Sully, United States

Last updated: June 24, 2025

In December, the average temperature in Sully, United States hovers around 0°C (31°F), making it a brisk time of year. Be prepared for temperature swings, with minimums plummeting to -23°C (-8°F) and maximums rising to a pleasant 23°C (73°F). During this month, you can expect about 40 mm (1.6 in) of precipitation over approximately 5 days, contributing to an average humidity level of 83%.

December Temperature in Sully

In December in Sully, the average temperature is 0°C (31°F). Maximums can reach 23°C (73°F) and minimums can be as low as -23°C (-8°F). This variety in temperatures makes Sully an interesting destination for travelers looking for both chilly and mild weather experiences.

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

The chart illustrates December temperature patterns in Sully, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sully, December typically has an average temperature of 0°C (31°F), with highs reaching up to 23°C (73°F) and lows dropping to around -23°C (-8°F).

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

December Precipitation in Sully

In Sully in December, the precipitation amount is 40 mm (1.6 in) over the course of 5 days.

December Precipitation Trends in Sully

The chart displays monthly precipitation patterns in Sully, 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 Sully, December typically receives around 40 mm (1.6 inches) of precipitation spread over approximately 5 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 Sully

In Sully in December humidity is 83%. With an average temperature of 0°C (31°F), this humidity feels like a biting chill that penetrates layers of clothing, making even short excursions feel daunting and uncomfortable.

December Average Humidity in Sully

This chart illustrates the average monthly humidity levels in Sully, 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 Sully is approximately 83%, 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 Sully

In Sully 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 Sully, you can check the information here.

Maximum UV Index Levels in Sully for December

The chart shows the monthly maximum UV Index (UVI) for Sully 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 Sully typically reaches 3, which falls under the moderate exposure category.

Data source: Sully 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 Sully Compares to Other Months

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

This table compares monthly weather conditions in Sully, 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)	44 mm (1.7 inches)	78%	moderate
February Weather	-4°C (24°F)	49 mm (1.9 inches)	80%	moderate
March Weather	4°C (40°F)	83 mm (3.3 inches)	77%	high
April Weather	10°C (50°F)	74 mm (2.9 inches)	77%	very high
May Weather	17°C (63°F)	163 mm (6.4 inches)	77%	very high
June Weather	23°C (74°F)	124 mm (4.9 inches)	81%	extreme
July Weather	25°C (77°F)	72 mm (2.8 inches)	81%	very high
August Weather	23°C (74°F)	65 mm (2.5 inches)	77%	very high
September Weather	20°C (69°F)	121 mm (4.8 inches)	73%	very high
October Weather	12°C (53°F)	137 mm (5.4 inches)	75%	high
November Weather	4°C (39°F)	49 mm (1.9 inches)	85%	moderate
December Weather	0°C (31°F)	40 mm (1.6 inches)	83%	moderate