September in Zagreb averages a daily high of 22.4°C with nights around 13.8°C. Expect roughly 10.8 wet days totalling 107.7mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Zagreb is April–October.
Based on ZAGREB GRIC, HR (0.3km), 1995–2024. 29 years of September data.