August in Kostroma averages a daily high of 22.2°C with nights around 11.9°C. Expect roughly 12 wet days totalling 73.7mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Kostroma is May–August.
Based on KOSTROMA, RS (5.9km), 1995–2024. 24 years of August data.