It's probably wiser to leave this up to next year's teachers. Your child takes responsibility. Grandparents can help. Your child can work with an older sibling. This can be a baby-sitter, a college student, a professional tutor, a teacher or aide who wants to work over the summer, or a senior citizen or retired person.
Schools often offer such programs or sometimes they are available privately.
Cost is a factor. Very good programs help kids acquire new skills and practice old ones. Unfortunately, they do not do a very good job of connecting the learning that has just taken place in school or building a bridge to fall.