September in Omsk averages a daily high of 16.4°C with nights around 5.8°C. Expect roughly 9.3 wet days totalling 26.8mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Omsk is May–September.
Based on OMSK, RS (2.9km), 1995–2024. 24 years of September data.