September in Gatchina averages a daily high of 16°C with nights around 6.4°C. Expect roughly 12.8 wet days totalling 56.8mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Gatchina is May–August.
Based on BELOGORKA, RS (19.7km), 1995–2024. 29 years of September data.