I've always lived in the deep South or lower Midwest, and school has always started mid-August and ended sometime toward the end of May, except for high school seniors, who usually get out at least a week early. DD attends a private HS, and she has been at school for 1/2 days this week as a upperclassman counselor for their freshman "good start" program (for kids who are a bit at risk, academically.) Her own classes start on Aug14th. As it now stands, the last day of class is scheduled for May 17th, with 3 days of final exams the following week, except for the seniors, who finish exams May 8th and graduate May 10th.
If we're going to vacation in the South, we often do it the final week before school starts, because most of the time we start about a week later than schools in the deep South do. FWIW, my eldest was born on May 25th, and when he was in school his birthday was almost always the first day of summer vacation. (When he started college in the South he started in the summer term, and I remember that he had 2 weeks off that year before he had to be on campus on June 4th.) We do have snow days built into the calendar, but the only year I can recall where we ran short was 2019-2020. However, with the pandemic raging, by the end of the school year no one cared, so they just closed down without trying to make up those days.
My understanding is that the public schools here mostly will start back on Aug 21st. The schools here (lower Midwest) are still not all air-conditioned, and as a result, the first 2 weeks of classes often end up being declared half-days at those older schools. It's very seldom so hot in May that that happens, so I guess the rationale is that losing some classroom hours in the first two weeks or so is better than losing them toward the end of the academic year.
