July in Janesville averages a daily high of 28.7°C with nights around 16.5°C. Expect roughly 10.1 wet days totalling 114.1mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Janesville is May–September.
Based on AFTON JANESVILLE WWTP, WI US (6.3km), 1995–2024. 29 years of July data.