January Weather in Vacaville, United States

Last updated: June 24, 2025

In January, the average temperature in Vacaville, United States hovers around 10°C (50°F), with a minimum dipping to -1°C (30°F) and a maximum reaching up to 26°C (79°F). Expect about 119 mm (4.7 in) of precipitation spread over 8 days, while the air maintains a high average humidity of 84%.

January Temperature in Vacaville

In January in Vacaville, the average temperature is 10°C (50°F). Maximums can reach 26°C (79°F), while minimums can drop as low as -1°C (30°F). Pack accordingly to enjoy a comfortable trip, as temperatures can vary significantly during your stay.

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

The chart illustrates January 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, January typically has an average temperature of 10°C (50°F), with highs reaching up to 26°C (79°F) and lows dropping to around -1°C (30°F).

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

January Precipitation in Vacaville

In Vacaville in January, the precipitation amount is 119 mm (4.7 in) over a span of 8 days.

January Precipitation Trends in Vacaville

The chart displays monthly precipitation patterns in Vacaville, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In Vacaville, January typically receives around 119 mm (4.7 inches) of precipitation spread over approximately 8 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

January Humidity in Vacaville

In Vacaville in January, humidity is 84%. With an average temperature of 10°C (50°F), this humidity feels like a chilly dampness that clings to your skin, making outdoor activities less comfortable and prompting travelers to seek refuge in cozy, warm cafes or indoor attractions.

January Average Humidity in Vacaville

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

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

January UV Index in Vacaville

In Vacaville in January, 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 January

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

Data source: Vacaville January 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 January 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 January’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 January’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