Over the last few years in the US. They've been starting the school year early. Some of the schools are as early to the middle of August (to my knowledge that is), and it goes until the end of may to the beginning or middle of June depending on what area or which school you're in. Also, as for breaks, We have Columbus Day which is around October and that is usually a day off in October (3 days if you add the weekend), then there's thanksgiving break which is a whole week off, Christmas break around 2-3 weeks, spring break (just had it a few weeks ago) a free week off, and that's about it... My semester ends the beginning of May so there's that... I would also talk about the catholic schools but I don't feel like clouding this VM right now.
P.S. The extended summer thing is mostly true...but like I said, they started to extend the school years so its summer break is shortened a bit depending on what school or part of the US you're in