April in Rijeka averages a daily high of 17.8°C with nights around 9.5°C. Expect roughly 11.1 wet days totalling 103.5mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Rijeka is May–June.
Based on RIJEKA, HR (0.9km), 1995–2024. 29 years of April data.