April in Iwamizawa averages a daily high of 11.6°C. Expect roughly 11.6 wet days totalling 52.9mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Iwamizawa is June–September.
Based on IWAMIZAWA, JA (2.6km), 1995–2024. 28 years of April data.