Heat index values made it up to 100 degrees across several cities in the Miami Valley Tuesday afternoon.
The relative humidity is factored into the heat index. Humidity is the measurement of moisture in the air. It is more difficult to cool down when there is a lot of moisture in the air.
When the body temperature rises above 98.6 degrees sweat develops. When the water droplets evaporate the body will cool down through a process known as evaporative cooling.
The higher the humidity the slower the evaporation rate is and the longer it takes to cool down.
It will be even hotter Wednesday and Thursday, as highs top out near 90-degrees and the heat index approaches 100. There is a chance the feels like temperature will go just over 100 Thursday afternoon. Relief arrives with a cold front Friday, and the weekend looks much more comfortable.