The heat index is a measure of how hot it feels to the human body. The index combines the actual temperature and the amount of humidity in the air to determine the "apparent temperature," also known as the heat index.
The formula for heat index is actually quite complex.
Take a look at the equation. You can see the two variables are temperature (T) and relative humidity (RH).
The heat index correlates directly to the humidity. The more humid it is the higher the heat index. The less humid, the lower the heat index is.
For instance, on a day like today when temperatures are in the middle-90s and the dew point is around 70 degrees, the heat index or apparent temperature is near 100 degrees.
Stay with the NBC Connecticut First Alert Weather Team for updates through the heat wave.