I was born, and raised in Rochester, New York. We had no air conditioning in our schools, just windows. I can still remember sitting in the gymnasium taking final exams in June, and sweating so badly that your hands stuck to the test papers, and your ass stuck to the plastic chair. We females couldn't wear shorts or slacks back then. Dresses or skirts and blouses only.
That's back when school was FUN.... for boys. ;-)
I can still remember...
A couple kids would distract our instructor and a couple others went out though the windows! I was not part of this - I just watched with amazement.
OTOH, Geometry Class was on the 2nd floor, and I was known to fly paper airplanes out the window when the instructor was looking away, bending them such that they’d make a slow turn for the windows on the 1st floor.
I grew up here in the Big Valley, where 100+deg is not unusual for September, May and June.
No AC in any classroom through High School.
Nothing but windows.
We were out the door at 2:10pm because first class was 7:15am.