January Weather in Janesville, United States

Last updated: June 24, 2025

In January, the average temperature in Janesville, United States hovers around -8°C (17°F). Prepare for chilly extremes, as temperatures can plummet to a minimum of -34°C (-30°F) or rise to a maximum of 9°C (48°F). Expect 34 mm (1.3 in) of precipitation over 5 days, and don't forget to bundle up, as the average humidity sits at a brisk 82%!

January Temperature in Janesville

In January in Janesville, the average temperature is -8°C (17°F). The maximum can reach 9°C (48°F), while the minimum can drop as low as -34°C (-30°F). Travelers should be prepared for extreme cold conditions, so layering and proper winter gear are essential for comfort and safety.

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

The chart illustrates January temperature patterns in Janesville, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Janesville, January typically has an average temperature of -8°C (17°F), with highs reaching up to 9°C (48°F) and lows dropping to around -34°C (-30°F).

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

January Precipitation in Janesville

In Janesville in January, the precipitation amount is 34 mm (1.3 in) over the course of 5 days.

January Precipitation Trends in Janesville

The chart displays monthly precipitation patterns in Janesville, 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 Janesville, January typically receives around 34 mm (1.3 inches) of precipitation spread over approximately 5 days.

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

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Millimeters (mm) Inches (in)

January Humidity in Janesville

In Janesville in January, humidity is 82%. With an average temperature of -8°C (17°F), this humidity feels like a biting chill that penetrates your layers, making traveling outdoors a brisk and uncomfortable experience.

January Average Humidity in Janesville

This chart illustrates the average monthly humidity levels in Janesville, 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 Janesville is approximately 82%, 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 Janesville

In Janesville 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 Janesville, you can check the information here.

Maximum UV Index Levels in Janesville for January

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

Data source: Janesville 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 Janesville Compares to Other Months

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

This table compares monthly weather conditions in Janesville, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-8°C (17°F)	34 mm (1.3 inches)	82%	moderate
February Weather	-9°C (17°F)	41 mm (1.6 inches)	84%	moderate
March Weather	1°C (34°F)	68 mm (2.7 inches)	80%	moderate
April Weather	7°C (45°F)	91 mm (3.6 inches)	81%	very high
May Weather	15°C (60°F)	140 mm (5.5 inches)	74%	very high
June Weather	22°C (72°F)	118 mm (4.7 inches)	80%	very high
July Weather	23°C (74°F)	103 mm (4.1 inches)	80%	very high
August Weather	21°C (71°F)	119 mm (4.7 inches)	77%	very high
September Weather	18°C (65°F)	137 mm (5.4 inches)	75%	very high
October Weather	9°C (49°F)	93 mm (3.7 inches)	80%	moderate
November Weather	1°C (35°F)	36 mm (1.4 inches)	87%	moderate
December Weather	-4°C (25°F)	44 mm (1.7 inches)	83%	moderate