September in Portage Park averages a daily high of 24.4°C with nights around 13.7°C. Expect roughly 8.1 wet days totalling 77.4mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Portage Park is August–September.
Based on CHICAGO OHARE INTERNATIONAL AIRPORT, IL US (13.8km), 1995–2024. 30 years of September data.