September in Kostanay averages a daily high of 19.4°C with nights around 7.4°C. Expect roughly 7 wet days totalling 27.4mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Kostanay is May–September.
Based on KUSTANAI, KZ (0.6km), 1995–2024. 15 years of September data.