Rilian
My dad said the summer thing started so that kids could help on the farm in summer. He grew up on a farm, but I don't personally know anything about it.
Doesn't actually make sense. Farmers need their kids in the spring for crop planting and in the fall for harvest and slaughter.
It's much more likely that summer vacation got started because summer is HOT. You can stoke the fire to warm up a school room in the winter, but there's not a lot you can do to cool off in the middle of a city classroom, before air conditioning.
At any rate, with modern air conditioning, having a 2 1/2 month summer vacation is pretty silly.