I am not a parent, but I was a kid once. And even though I absolutely recognize the importance of education (I have two undergraduate degrees and a masters), I am a strong proponent of learning outside the classroom — and even outside of school.
That's why summer vacation is so important — and so is even more time off and time away, if you can get away with it. I did, and I graduated from high school and college on time. School is great, but it's not the only place to learn.
When I was 9, I missed a year of school (fourth grade), when I moved for almost a year to Australia, which has an opposite school schedule to the U.S. (There, they start the new academic year after Christmas in January, so they get summer break and Christmas break all at once.) I had a few weeks of school in the U.S. before we left, and a few weeks of class in Australia before we returned, but aside from learning all six Australian states and how differently American history is taught everywhere else (let's just say nobody glorifies the Revolutionary War like we do), I didn't learn much. Well, not much "book-learning," that is.
But I did get the chance to visit a number of Australian wildlife refuges and learn about the unique life cycles of marsupials, read many of the Aussie children's books that I hadn't checked out yet, and was steeped in the culture that half my family hailed from, but that I wasn't very familiar with. And yes, I also spent a lot of time in the pool and at the beach too, mostly with a girl about my own age from Pakistan who had recently immigrated to Australia. Not only did I help her with her English, but I learned how differently girls grow up in other places. Looking back, I can see that spending time staring at the tiny creatures in tidal pools for hours during completely unstructured beach trips can teach a kid a lot about how ecological niche communities work. Later I went on to study starfish predation on the coast of Maine and major in biology.
My grandmother, who liked to travel, also took me out of school a number of other times — when she got a good deal on a flight to an exotic locale, when it was a nice day to work outside in the garden, and when I didn't feel like going to school. (Whether I was physically or mentally not feeling it, I wasn't made to go.) When I took more than a day off, I was told to keep a journal of my travel impressions, which I would hand in my teacher at the end of the voyage. (Yes, I went to public school, but I was also in a very small town. I think this might be harder to get away with today.)
Because going to school was never a punishment, I didn't see it as one, but (usually) as a place I wanted to go. And I think it's part of the reason I've pursued educational goals — because I genuinely love it. I'm currently weighing PhD programs.
When people ask me where my green thumb comes from, I think back to the time I spent gardening the day away — not in school. My love of reading and writing comes directly from spending those many days that I wasn't in school indulging in the wonderful joy of all-day reading (usually in one of my self-designed forts in the woods surrounding my childhood home).
When I hear people suggesting that school should be a year-round experience, I grimace. Fresh air, days filled with "nothing" (learning how to fill that time is a lesson in and of itself), six hours straight of involved reading, learning about new cultures, having time to watch songbirds, tide pool denizens or my own cat hunt down a vole, seeing things for yourself and not just reading about them in a book — all of these are just as important as school. Or at least they were for me.