May in Ishim averages a daily high of 18.7°C with nights around 5.8°C. Expect roughly 11.2 wet days totalling 40.4mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Ishim is May–August.
Based on ISCHIM AMSG, RS (3.8km), 1995–2024. 25 years of May data.