July in Mount Prospect averages a daily high of 28.8°C with nights around 18.3°C. Expect roughly 9 wet days totalling 87.6mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Mount Prospect is May–September.
Based on CHICAGO PALWAUKEE AIRPORT, IL US (6.6km), 1995–2024. 29 years of July data.