What is the heat index?

Weather News

CHICOPEE, Mass. (WWLP) – A heat advisory is in effect for heat indices reaching near 100 degrees. But what exactly is a heat index?

It’s something that is calculated factoring in the humidity and the actual temperature to give a feels-like temperature. This is the summer version of the wind chill temperature we get in the winter. It’s not just heat that can be dangerous, the humidity plays a huge part in the risk for heat illness.


Here’s why. When it’s dry and hot outside, when your body sweats, that sweat is evaporated quickly off of your skin. And that’s a cooling process, so it helps you regulate your body temperature. It’s the same reason you feel a little chilly when you first get out of a pool on a summer day. But, when it’s humid, there’s more water in the air, that makes it harder for the sweat on your skin to evaporate, making it more difficult for your body to regulate its temperature, increasing the risk for heat illness.

Wednesday through Friday, temperatures will be highs in the 90s, but oppressive levels of humidity with dew points in the 70s. That creates those heat indices near and over 100 degrees. 

Copyright 2021 Nexstar Media Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

Only on WWLP.com | Digital First

More Digital First

Trending Stories

Donate Today