Heat Index: What Does it Really Mean?
The Heat Index, like its wintertime counterpart Wind Chill, is a way to understand how humans and their pets and livestock respond to the combination of temperature and other related weather elements. In the case of the Heat Index, a very involved empirical formula is used to approximate the combined impact of heat and humidity on both humans and animals. In short, when the dew point is at or above 60 degrees, the formula adds degrees to the ambient air temperature to give a more accurate understanding of the physiological effect conditions have on those who are outside enduring them. In the cold season, the air temperature and sustained wind are used in another empirical formula that results in Wind Chill.