April in Wŏnsan averages a daily high of 16.8°C with nights around 6.5°C. Expect roughly 8 wet days totalling 88.9mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Wŏnsan is September–October.
Based on WONSAN, KN (3.5km), 1995–2024. 21 years of April data.