January in Ōnojō averages a daily high of 10.1°C. Expect roughly 11.5 wet days totalling 67.9mm. 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. 23 years of January data.