Updated

Students throughout the Midwest are getting out of school early this week because of sweltering temperatures and a lack of air conditioning in some classrooms.

Schools in Nebraska, Iowa, the Dakotas and Illinois planned to release children in the early afternoon, before temperatures reached expected highs — nearly 100 degrees in much of the central United States.

School administrators in several states said they were letting school out early because of safety concerns for students and teachers. Many schools have air conditioning systems that don't extend throughout the entire building.

The National Weather Service says a prolonged heat wave of this magnitude is unusual for this time of year, but not unprecedented.