December in Kostanay averages a daily high of -7.3°C with nights around -15.6°C. Expect roughly 10.9 wet days totalling 26.5mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Kostanay is May–September.
Based on KUSTANAI, KZ (0.6km), 1995–2024. 12 years of December data.