September in Dayton averages a daily high of 26.5°C with nights around 14.3°C. Expect roughly 8 wet days totalling 76.8mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Dayton is September–October.
Based on DAYTON MCD, OH US (2.5km), 1995–2024. 23 years of September data.