September in Incheon averages a daily high of 26.1°C with nights around 17.4°C. Expect roughly 8.8 wet days totalling 131.9mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Incheon is May–June.
Based on INCHEON, KS (6.5km), 1995–2024. 22 years of September data.