September in Kiryū averages a daily high of 27.6°C. Expect roughly 12.8 wet days totalling 187.8mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Kiryū is September–November.
Based on MAEBASHI, JA (23.8km), 1995–2024. 21 years of September data.