September in Decatur averages a daily high of 28.2°C with nights around 17.8°C. Expect roughly 6.7 wet days totalling 98.8mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Decatur is April–May.
Based on DECATUR 4 SE, AL US (5.6km), 1995–2024. 18 years of September data.