The combination of heat and humidity forced many schools in the Tri-State area to dismiss early Tuesday.
From Hannibal to Fort Madison and a handful of Illinois school districts, schools without air conditioning just couldn't beat the heat.
So when is it too hot to stay in class? This year, Central School District came up with a new set of guidelines to determine early dismissals.
"This summer was a summer where, with 100 degree heat, we knew that at the beginning of the year, that was going to be an issue. So the superintendents of Pittsfield, Southeastern and I got together for about three weeks this summer and we decided to address a plan that would determine how to get out for heat," Superintendent Marty Cook said.
Cook and his colleagues now check the heat index through the National Weather Service three times during the school day at 9 a.m., 11 a.m., and 1 p.m. If the heat index reaches 95, it's an automatic early dismissal. Cook says this is different than just focusing on the temperature itself. The new guidelines also take into consideration the humidity, which is a bigger factor inside the school.
"With parents in our communities, they know daycare is going to be a problem with early dismissals, but we wanted to come up with something that would let them know if we reach this temperature, this heat index, anticipate an early dismissal," Cook said.
Cook says later in the fall, he'll check back with his teachers to see whether or not the 95 degree scale worked well or if it needs to come down to a cooler index.
"It's been a plus for us, because we have to deal with heat every year, so we might as well come up with a definitive number that will help us make that decision," Cook said.
For the latest school closings and early dismissals in our area, click here .