Janesville (WI) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Janesville.
Climate overview of Janesville
The climate in Janesville, Wisconsin, United States of America, is marked by large temperature swings across the seasons, ranging from 28°C (82°F) in July to -2°C (28°F) in January.
The city receives considerable rain/snowfall, with around 1013 mm (40 in) annually. June is the wettest month. It has warm summers and very cold winters. July is the sunniest month, averaging 10.3 hours of sunshine per day.
Janesville Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Janesville - and find the best time to visit.
Monthly Temperature in Janesville
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
Rainfall in Janesville
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
Sunshine Hours in Janesville
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
Humidity in Janesville by Month
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
Best Time to Visit Janesville
Monthly ratings reflect general weather comfort, based on daytime temperature and rainfall. Swimming and winter conditions are highlighted separately where relevant.
- Best overall: May, July and September
- Warmest weather: July and August
- Most sunshine: June and July
- Seasonal pattern: Warm summers and very cold winters
- Coldest conditions: January, with freezing nights around -11°C (12°F).
Frequently asked questions about the climate in Janesville
What is the best time to visit Janesville?
May, July and September typically offer the most optimal weather in Janesville. In contrast, January, February, March, November and December tend to have less optimal conditions. Janesville has warm summers and very cold winters.
What temperatures can I expect in Janesville?
Daytime highs range from -2°C (28°F) in January to 28°C (82°F) in July. Nighttime lows range from -11°C (12°F) to 16°C (61°F). Temperatures vary considerably through the year.
How much rain does Janesville get?
Annual rainfall is around 1013 mm (40 in). June is the wettest month with 139 mm (5.5 in), while January is the driest with 36 mm (1.4 in).
How sunny is Janesville?
Janesville receives around 2,454 hours of sunshine per year. July is the sunniest month with 308 hours, while December is the cloudiest with just 107 hours. Overall, Janesville enjoys abundant sunshine.
Janesville 3-Day Forecast
Janesville (WI) 3-Day Forecast
Janesville on the map
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