September in Gary averages a daily high of 23.7°C with nights around 13.5°C. Expect roughly 9.2 wet days totalling 83.9mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Gary is May–September.
Based on INDIANA DUNES NATIONAL PARK, IN US (21.9km), 1995–2024. 26 years of September data.