September in Banja Luka averages a daily high of 24.3°C with nights around 11.5°C. Expect roughly 10 wet days totalling 138.7mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Banja Luka is April–June.
Based on BANJA LUKA, BK (1km), 1995–2024. 11 years of September data.