April in Kostroma averages a daily high of 10.2°C with nights around 0.8°C. Expect roughly 10.7 wet days totalling 33.8mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Kostroma is May–August.
Based on KOSTROMA, RS (5.9km), 1995–2024. 26 years of April data.