May in Kaiyuan averages a daily high of 28.4°C with nights around 19.1°C. Expect roughly 11.8 wet days totalling 88.4mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Kaiyuan is November–March.
Based on MENGZI, CH (35.9km), 1995–2024. 24 years of May data.