The official visitor guide for Chuncheon National Museum says that although the main museum and Children's Museum normally close on Mondays, the outdoor garden stays open free of charge even on museum closure days. When Monday is a public holiday, the museum may open then and substitute the next weekday for the closure.
Main-gallery hours are 09:00–18:00, with admission closing 30 minutes early. Children's Museum hours are 09:30–17:30, last entry 17:00, while the infant and toddler area runs 10:00–17:00.
Free access to the outdoor garden does not imply indoor children's activities remain open. Visitors planning a garden-only visit on a closure day should check garden access and weather conditions, and schedule indoor activities for a normal opening day.