0 a measurement of how hot the air feels and how uncomfortable people are likely to be based on the temperature combined with the humidity (= the amount of water in the air):
With the heat index up, all I really want is to just chill out.
The battery-powered device measures temperature, barometric pressure, heat index, wind speed, and even altitude.
Many of the streets are treeless ovens in the 90-degree plus heat index.
There's even a heat index for pungency of foods, particularly peppers, based on how much capsaicin (the heat-inducing stuff) they contain.
