PEORIA, Ill. (WMBD) – Two things we tend to hear a lot when summer rolls around are heat index, and dew point.
The dew point is used to figure things like humidity and plays a role in the development of thunderstorms. Dew point is also used in how we figure the heat index.
The heat index temperature is how the air feels to the human body when the air temperature is combined with relative humidity.
The relative humidity comes from the dew point. The dew point refers to the temperature at which water can condense and form dew, or just condense into droplets.
When the dew point is high, that means there is a lot of moisture in the atmosphere. When there is more moisture in the air, then the sweat produced by the body can’t evaporate and cool you down.
This is where the heat index comes in. When the temperatures begin to climb and there’s plenty of moisture, then it feels humid, or muggy.
Dew point temperatures increase and so does the relative humidity. Both of these make it feel even hotter outside. The temperature it feels like outside with these two things factored in gives us the heat index.
Other things that can factor into how the air feels outside are sunshine and winds. If you have a fully sunny day, then it will feel even hotter. Warm air will add to this feeling as well, along with helping to add moisture to the air.
When it comes to heat, there are a few different warnings that can be produced. Heat advisories are issued ahead of dangerous heat events.
Usually when the heat index is expected to be 100° or higher for two or more days. An excessive heat warning is issued during extremely dangerous heat, usually when the heat index is 105° or higher for at least two days.
Heat exhaustion and heat stroke are two things that can set in quickly during these times of extreme heat. Try to limit your time outside or stay inside. If you do work outdoors, make sure you stay hydrated and take breaks from the heat.