A Houston ISD elementary school was forced to close its doors Wednesday due to what the district called an “HVAC system outage.” The school has since reopened, but it’s one of several HISD campuses KPRC 2 has been covering that have had A/C-related issues.

More and more HISD schools are turning up with hot classrooms and broken AC systems. Outside Margaret Long Wisdom High School on a sweltering day in Houston, the outside mural says “where the world comes to learn”, but maybe it should be “where the world comes to sweat.”

Yes. It's hot. But how hot is it? And what does it mean when our meteorologists tell us we're under a heat warning, watch, or advisory?