April in Ongjin averages a daily high of 16.3°C with nights around 6.7°C. Expect roughly 7 wet days totalling 57.6mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Ongjin is September–October.
Based on HAEJU, KN (31.6km), 1995–2024. 23 years of April data.