I don't go to school anymore either, but when I did, it always started on the last monday of August, and ends sometime in June (depends on how many snowdays we got). On a full day, we have to wake up at least by 6:00 AM to get ready but we don't have to be in the classroom until 7:50 AM I think. Then we get dismissed from school at 2:25 PM. Those who can drive or have a ride can leave. Those who have to get on the bus have to, of course, find their designated bus and wait until around 2:30-2:35 before the busses leave and drop us off at home.
On half days, it's the same time getting to school, but we get dismissed at 12:30 PM I believe. On 2 hour delays, we don't have to be in the school until 9:50 I believe. And on days when the weather gets bad, it's usually at 1:30 we're dismissed, not sure. On the last week or two of school, the days are cut short and we get dismissed at 11:30 AM. Lunch is no longer served at this point. On the very last school day (which we do not need to attend), we only stay until 10:30 AM. This day is mandatory for middle-schoolers but for high-schoolers, this day is optional. It's just a socializing day where you can meet and talk with your friends, sign year books, all that.