September in Rockford averages a daily high of 24.6°C with nights around 11.9°C. Expect roughly 7.8 wet days totalling 85.9mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Rockford is August–September.
Based on ROCKFORD GREATER ROCKFORD AIRPORT, IL US (8.7km), 1995–2024. 30 years of September data.