The heat index is used all the time during the summer to illustrate how hot it feels outside. Meteorologists use it in many cases to drive home a really hot forecast. Thats great, but I'm not so sure that everyone actually realizes what the heat index is, or what it means. So, I figured I would throw out a few facts about this important summertime weather tool.
Anybody who watches the weather in the summer knows that the heat index combines air temperature and relative humidity to give an apparent temperature, or what it "feels like" outside. But why exactly does humidity make it feel hotter? It all has to do with the human body's cooling system. The body cools itself primarily through perspiration (sweat). The sweat that forms on the skin evaporates and carries body heat away with it, thus cooling the body down.
This functions normally when it is relatively dry outside. When it is relatively more humid outside, the sweat cannot evaporate as fast or as much, because the surrounding air is already full of water vapor. Since the sweat does not evaporate as well, the body cannot cool itself as efficiently, and this makes the body feel hotter. This can be a dangerous situation if someone stays outside for too long in this type of environment. If the body is still unable to cool itself for a period of time, its core temperature will begin to rise, and this could lead to heat stroke and eventually death.
More Heat Index and other weather stuff next time . . .
Drew McCombs
ABC 33/40 Weather Intern
abc3340wx2@gmail.com
Anybody who watches the weather in the summer knows that the heat index combines air temperature and relative humidity to give an apparent temperature, or what it "feels like" outside. But why exactly does humidity make it feel hotter? It all has to do with the human body's cooling system. The body cools itself primarily through perspiration (sweat). The sweat that forms on the skin evaporates and carries body heat away with it, thus cooling the body down.
This functions normally when it is relatively dry outside. When it is relatively more humid outside, the sweat cannot evaporate as fast or as much, because the surrounding air is already full of water vapor. Since the sweat does not evaporate as well, the body cannot cool itself as efficiently, and this makes the body feel hotter. This can be a dangerous situation if someone stays outside for too long in this type of environment. If the body is still unable to cool itself for a period of time, its core temperature will begin to rise, and this could lead to heat stroke and eventually death.
More Heat Index and other weather stuff next time . . .
Drew McCombs
ABC 33/40 Weather Intern
abc3340wx2@gmail.com