Heh. Though teachers have the time off, they rarely use all of it for just vacation.
In my area, school gets out usually the first week of June, and school starts at the end of August. We get about two weeks at Christmas and a week at the end of March (for spring break), and then a total of seven to nine weeks for summer. This year, it would have been seven.
However, once school starts, if you don't have the majority of your lessons planned, you're going to be working more than the normal 10+ hour days because you can't plan at school. There's no freakin' way.