When people hear you're taking your family to Hawaii in January, they assume it'll be cold. We spent three weeks island-hopping between Oahu and Kauai with kids under 10, swimming every day and discovering that January is one of the best times for a family trip to the islands. This complete guide covers what's worth your time on each island, which activities to book in advance, where to find the best food, and the moments that actually matter spoiler: it's rarely the Instagra