Reply #13: Wow. You actually have no idea, do you?

[The Doctor.]

The 'Heat Index' was not 'concocted by TV weathermen.'

Mere temperature readings do not factor in the human body, which reacts to more than just temperature. The Heat Index takes humidity into account due to it's effect on our cooling system. As the temperature rises, humidity becomes more serious due to the air's diminished ability to absorb evaporated perspiration. The body doesn't cool by sweating, it cools by having the sweat evaporate, thereby taking the excess heat with it. The warmer it gets, the more a body needs perspiration to evaporate into the air. The higher the humidity, the less a body is able to shed excess heat.

Unfortunately, there are plenty of people who can't or won't understand basic physiology and physics. That is why a simple 'Heat Index' was designed to convey the danger of hot and humid weather.

Would I be hoping for too much for you to have now learned what it actually is?