September in Charleston averages a daily high of 28.4°C with nights around 22.6°C. Expect roughly 8.7 wet days totalling 128.9mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Charleston is March–May.
Based on DOWNTOWN CHARLESTON, SC US (0.8km), 1995–2024. 29 years of September data.