But the good ones work a 12-hour day when you include grading and prep done at home.
Yep - my wife is a high school chemistry teacher and easily puts in 8 hour days at the school, then a few more at home each evening.
That, and I don't know why people assume summer vacation is 3 months long. Here in Connecticut, the public schools get out mid-to-late June, and start up again the last week of August - that's about 8 or 9 weeks. The private and Parochial schools get out even earlier - end of May, and start up again same time as the public schools.