Janesville (WI) Weather & Climate: Best Time to Visit

In Janesville, temperatures differ significantly between summer and winter months. Typically, average maximum daytime temperatures range from a comfortable 28°C (82°F) in July to a very cold -2°C (28°F) in the coolest month, January.

Nights vary from 16°C (61°F) in July to around -11°C (12°F) during the colder months.

Check out our detailed temperature page for more information.

Temperature ranges by month

Janesville experiences significant rain/snowfall throughout the year, averaging 1013 mm (40 in) of precipitation annually. The climate in Janesville shows significant variation throughout the year. Expect high rainfall in June, the wettest month, with an average of 139 mm (5.5 in) of precipitation over 13 rainy days.

In contrast, the driest month January offers drier and sunnier days, with around 36 mm (1.4 in) of snowfall over 10 snowy days. For more details, please visit our Janesville Precipitation page.

The mean monthly precipitation over the year, including rain, hail, and snow

The average number of days each month with precipitation

For those who appreciate different seasons, Janesville serves as an ideal destination. Expect longer, more sun-filled days in July with an average of 10.3 hours of sunshine daily, and embrace the darker days in December, offering only 3.6 hours of daily sunlight.

Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Daily hours of sunshine

Daily percentage of sunshine

The relative humidity is high throughout the year in Janesville.

The city experiences its highest humidity in December, reaching 77%. In May, the humidity drops to its lowest level at 65%. What does this mean? Read our detailed page on humidity levels for further details.

Relative humidity over the year