I am a HUGE advocate for the "year-round" school. we have exactly ONE in my district. My kids went there until 4th grade.
Basically they go to school from Early August until mid June, so they have a 6 week summer. Much less learning loss. They still go to school for the same amount of days, but they have extra breaks built into the school year. We would do Beach trips in October, and we did Disney in February. During the intersessions they offer fun educational "camps."