August in Yotsukaidō averages a daily high of 31.4°C. Expect roughly 9.7 wet days totalling 121.7mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Yotsukaidō is April–June.
Based on CHIBA, JA (8.2km), 1995–2024. 24 years of August data.