As a result, school districts are seeing their protection policies put to the test in the early going.
At 87 degrees, the kids at Pyle Elementary are bouncing around the playground during recess.
A little mist from spray bottles and some games under the shade of trees help keep the kids from overheating. But when the temperature rises above 100, the games slow down.
The main focus for administrators is actually not heat, though. It's air quality, which usually gets worse when temperatures rise.
"When we get to red it's an unsafe situation and that's when we limit our activity on the blacktop. We limit our activity on the field, our running, our jumping, any activity like that we'll curtail it," Pyle Elementary Vice Principal Rob Roellke said.
Kids are among the most at-risk in extreme heat.
Dr. William Ebbeling says their body temperatures rise fast and outdoor temperatures over 105 degrees can be deadly.
Athletes are especially vulnerable because they're exerting themselves, so Ebbeling says afternoon practices can be dangerous.
"Get them there at 6 o'clock in the morning. Exercise them at that time. You don't want to exercise them when it's over 105. Once you do that, you're putting them at risk for heat shock," Dr. Ebbeling said.
The Hoover High School football team practiced in full pads Monday, but as the week progresses, they might have to take off their helmets and pads, or hit the field after 7 p.m.
"Our district has a policy in place that anything over 105, we shut down until the heat index goes below a certain number. Usually, it's after 7 in the evening when we're able to get back on," Hoover High Asst. Football Coach Rick Lyons said.
Coaches say they also make sure the kids are always getting water to keep their bodies cool.
Tuesday, the air pollution control district is calling for another orange flag day, but once those 100 degree days start, the red flags could come out.