How do American Schools Work?

this might be a weird question to ask but.....



You guys in america have summer vacation in the middle of the year. How long do you have off over christmas and when do u go up a grade?



in australia we have summer at the end and start of the year so thats our summer and christmas holidays and we change grades there. but do americans change grades in the middle of the year or at the end?How do American Schools Work?
Im not american but i know they have like 3 months off (summer holidays) in the middle of the year and that's when that go up a grade. Personally i think the way we have it in Australia is so much easier to understand.How do American Schools Work?
im not sure but i think they change grades in august or september

my cuz in another country has 3 months holidays in the middle of the year but they dont have any of those 2 weeks holidays