Why it matters: The heat index could reach as high as 110 today, which could be life-threatening if you don't protect yourself.
Stunning stat: The heat even forced changes at the rescheduled Music City Grand Prix last night, where organizers shortened the race from 300 laps to 225.
What now: Drink plenty of fluids and limit your time outdoors. If you must be outside, take breaks in the shade and ratchet up your water intake.
