Heat Index: What Is It

We use the term heat index a lot, but what exactly is it?

Posted: Jun 18, 2018 5:37 PM

TERRE HAUTE, Ind. (WTHI) - During the summer, when things get hot, we tend to use the term "heat index" a lot, but what exactly is it, and what does it mean?

First, you need to now how we find it.

The first thing we look at is the temperature, then we compare that with the relative humidity.

Relative humidity is the amount of moisture in the atmosphere.

The higher the humidity is, the more moisture is in the air, making it harder for sweat to evaporate.

When sweat doesn't evaporate quickly, we can't cool off as fast.

That's why when the humidity is high, it starts to feel sticky when you walk outside.

Say for example, the temperature is at 86 degrees.

Then on top of that, the relative humidity is at 70 percent.

At that temperature and relative humidity, the "feels like" temperature, (or heat index) is all the way up at 95 degrees.

This just goes to show how much of a factor heat index really plays.

The temperature can be warm, but not hot, and depending on how much humidity is in the air, things can feel much hotter than they really are.

As summer goes on, stick with Storm Team 10 for all the latest updates on conditions, especially when things start to get dangerously hot.

Article Comments

Terre Haute
Clear
63° wxIcon
Hi: 86° Lo: 61°
Feels Like: 63°
Robinson
Clear
59° wxIcon
Hi: 85° Lo: 58°
Feels Like: 59°
Indianapolis
Few Clouds
72° wxIcon
Hi: 87° Lo: 60°
Feels Like: 72°
Rockville
Clear
63° wxIcon
Hi: 85° Lo: 60°
Feels Like: 63°
Casey
Clear
85° wxIcon
Hi: 85° Lo: 60°
Feels Like: 85°
Brazil
Clear
63° wxIcon
Hi: 85° Lo: 61°
Feels Like: 63°
Marshall
Clear
63° wxIcon
Hi: 86° Lo: 60°
Feels Like: 63°
Dry and Dusty
WTHI Planner
WTHI Temps
WTHI Radar

Latest Video

Image

Old National Bank Classic

Image

Wednesday Late Forecast

Image

ISU Football

Image

THN Girls soccer

Image

Parents share how expenses can add up with travel sports

Image

Marines kick-off annual Toys for Tots campaign

Image

Vigo County kids make donations to area homeless

Image

Company gifts ISU $1.3 million in software

Image

‘It’s taught me a lot…’ VCSC students build skills one home at time

Image

Trade jobs in demand across Indiana

WTHI Events