Road crews, landscapers, and utility workers are just some of the people that have to work outside in this extreme heat.
So what are outdoor workers doing to beat the heat?
The asphalt workers I talked to Monday said they are focusing on two things: drinking lots of fluids and taking frequent breaks.
"When the temperature is about 100 degrees and the asphalt is about 300 degrees it gets a little rough sometimes, Jefferson Asphalt Donnie Champlain said.
Donnie Champlain battles hot asphalt and the beating sun almost every day.
"Whenever you feel like you need to sit for a minute you do. Then you get yourself a drink and go on, Champlain said.
Monday the temperature was in the upper nineties.
But if you stood on asphalt Monday it was a different story because the temperature was about 145 degrees, that's something MoDOT workers have to deal with almost every day in the summer.
"Anybody that's been out on the parking lots or you happen to go to theme parks where you're on that sunny pavement all day long you can feel the heat coming off the pavement radiating upwards. It's just really hard to get your body cooled off when your working on stuff like that, MoDOT Mike Belt said.
That's exactly why Belt said MoDOT supervisors watch for signs of heat exhaustion which include profuse sweating, nausea, vomiting, lightheadedness, and muscle cramps.
Belt told me workers in the summer are allowed to take more breaks than usual to avoid heat exhaustion.
"We ask them to take frequent short breaks in shaded areas or air conditioning to cool off a little bit and bring down their core body temperature, Belt said.
Belt said they also alternate road crews day-by-day, keeping them off the pavement on some of the days.
Tell us what you think. What are you doing to keep cool during this heat wave?