August in Ōnojō averages a daily high of 32.8°C. Expect roughly 12.1 wet days totalling 258.7mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Ōnojō is April–May.
Based on FUKUOKA, JA (10.3km), 1995–2024. 22 years of August data.