December Weather in Granby, United States

Last updated: June 24, 2025

In December, the average temperature in Granby, United States hovers around -9°C (15°F). However, temperatures can dip as low as -28°C (-19°F) or rise to a maximum of 9°C (49°F). During this month, expect 41 mm (1.6 in) of precipitation over approximately 10 days, with the air maintaining a humidity level of 89%.

December Temperature in Granby

In December in Granby, the average temperature is -9°C (15°F). Maximums can reach up to 9°C (49°F), while minimums can drop as low as -28°C (-19°F). Travelers should prepare for cold weather conditions and dress in layers to stay warm during their visit.

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

The chart illustrates December temperature patterns in Granby, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Granby, December typically has an average temperature of -9°C (15°F), with highs reaching up to 9°C (49°F) and lows dropping to around -28°C (-19°F).

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

December Precipitation in Granby

In Granby in December, the precipitation amount is 41 mm (1.6 in) spread over 10 days.

December Precipitation Trends in Granby

The chart displays monthly precipitation patterns in Granby, 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 Granby, December typically receives around 41 mm (1.6 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 Granby

In Granby in December, humidity is 89%. With an average temperature of -9°C (15°F), this humidity feels like walking through a thick fog, making it challenging to breathe and creating a sharp chill that penetrates even the warmest of clothing, which can be a struggle for travelers.

December Average Humidity in Granby

This chart illustrates the average monthly humidity levels in Granby, 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 Granby is approximately 89%, 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 Granby

In Granby in December, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Granby for better planning.

Maximum UV Index Levels in Granby for December

The chart shows the monthly maximum UV Index (UVI) for Granby 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 Granby typically reaches 4, which falls under the moderate exposure category.

Data source: Granby 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 Granby Compares to Other Months

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

This table compares monthly weather conditions in Granby, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-9°C (16°F)	38 mm (1.5 inches)	88%	moderate
February Weather	-8°C (19°F)	54 mm (2.1 inches)	87%	high
March Weather	-3°C (27°F)	58 mm (2.3 inches)	81%	very high
April Weather	0°C (32°F)	62 mm (2.4 inches)	76%	extreme
May Weather	4°C (39°F)	64 mm (2.5 inches)	66%	extreme
June Weather	11°C (52°F)	33 mm (1.3 inches)	58%	extreme
July Weather	15°C (59°F)	25 mm (1.0 inches)	52%	extreme
August Weather	14°C (58°F)	27 mm (1.1 inches)	56%	extreme
September Weather	11°C (51°F)	26 mm (1.0 inches)	65%	very high
October Weather	2°C (36°F)	50 mm (2.0 inches)	76%	high
November Weather	-4°C (24°F)	40 mm (1.6 inches)	82%	moderate
December Weather	-9°C (15°F)	41 mm (1.6 inches)	89%	moderate