December Weather in Vacaville, United States

Last updated: June 24, 2025

In December, the average temperature in Vacaville, United States is a pleasant 10°C (50°F), with daily highs reaching up to 24°C (75°F) and lows dropping to 1°C (35°F). Expect 85 mm (3.3 in) of precipitation over 8 days, along with an average humidity level of 83%—perfect for cozy indoor activities or exploring the charm of the season!

December Temperature in Vacaville

In December in Vacaville, the average temperature is 10°C (50°F). The maximum can reach 24°C (75°F), and the minimum can be as low as 1°C (35°F). This makes Vacaville an ideal destination for travelers seeking a mild climate with pleasant variations, perfect for exploring outdoor activities.

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

The chart illustrates December temperature patterns in Vacaville, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Vacaville, December typically has an average temperature of 10°C (50°F), with highs reaching up to 24°C (75°F) and lows dropping to around 1°C (35°F).

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

December Precipitation in Vacaville

In Vacaville in December, the precipitation amount is 85 mm (3.3 in) over the course of 8 days.

December Precipitation Trends in Vacaville

The chart displays monthly precipitation patterns in Vacaville, 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 Vacaville, December typically receives around 85 mm (3.3 inches) of precipitation spread over approximately 8 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 Vacaville

In Vacaville in December, humidity is 83%. With an average temperature of 10°C (50°F), this humidity feels like a damp chill that clings to your skin, making outdoor exploration less comfortable and prompting visitors to seek cozy indoor activities.

December Average Humidity in Vacaville

This chart illustrates the average monthly humidity levels in Vacaville, 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 Vacaville 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 Vacaville

In Vacaville 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 Vacaville, you can check the information here.

Maximum UV Index Levels in Vacaville for December

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

Data source: Vacaville 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 Vacaville Compares to Other Months

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

This table compares monthly weather conditions in Vacaville, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	10°C (50°F)	119 mm (4.7 inches)	84%	moderate
February Weather	12°C (53°F)	102 mm (4.0 inches)	84%	moderate
March Weather	13°C (56°F)	77 mm (3.0 inches)	83%	high
April Weather	16°C (61°F)	32 mm (1.3 inches)	81%	very high
May Weather	19°C (66°F)	17 mm (0.7 inches)	74%	very high
June Weather	22°C (71°F)	1 mm (0.1 inches)	64%	extreme
July Weather	22°C (71°F)	0 mm (0.0 inches)	44%	extreme
August Weather	22°C (72°F)	0 mm (0.0 inches)	36%	very high
September Weather	21°C (71°F)	1 mm (0.0 inches)	44%	very high
October Weather	18°C (65°F)	26 mm (1.0 inches)	65%	high
November Weather	13°C (56°F)	38 mm (1.5 inches)	84%	moderate
December Weather	10°C (50°F)	85 mm (3.3 inches)	83%	moderate