September in Kirishima averages a daily high of 30.4°C. Expect roughly 11.8 wet days totalling 244.8mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Kirishima is April–May.
Based on KAGOSHIMA, JA (29.3km), 1995–2024. 21 years of September data.