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What is wind chill?

Heat index and wind chill are both referred to as "feels like" temperatures, but they are different.

SAN ANTONIO — In Texas, meteorologists use heat index during the summer months, then switch to wind chill during the colder months. Both heat index and wind chill are referred to as what it "feels like" to the human body, but they are different. 

The heat index is when the temperature is combined with humidity.

Heat index chart:

Credit: National Weather Service
Heat index chart

Unlike heat index, wind chill factors in wind and temperature. The temperature must be 50 degrees or cooler and wind speed greater than 3 miles per hour. 

Heat index and wind chill play an important role in health during weather extremes.

Our KENS 5 Weather Team refers to wind chill to show what it "feels like" on our skin. 

The average temperature of the human body is 98.6 degrees. If there is no wind present our body will radiate heat, creating a thin layer of warmth above the skin. 

Credit: KENS
No wind, the body radiates heat, creating a thin layer of warmth above our skin.

On a windy day, the wind will strip away that warm layer making it feel much colder.  

Credit: KENS
Wind will move heat away from our bodies, making it feel colder.

The stronger the wind, the colder it will feel outside.

For example, if the outside temperature is 30 degrees with a wind speed at 20 miles per hour, we will have a wind chill (a "feels like" temperature) of 17 degrees!

The National Weather Service has a helpful chart in determining wind chill.

Credit: National Weather Service
Wind chill chart

You can determine the wind chill by finding the closet current temperature at the top and closest current wind speed on the side. Then follow where that column and row meet to get the current wind chill. 

The blue and purple-shaded areas on the wind chill chart show the amount of time it would take to get frostbite. 

A bitterly cold wind chill can increase your risk of getting hypothermia and frostbite. 

Here are 5 tips to stay warm and safe:

  1. Dress in layers. Don't forget your hat, scarf, and gloves!
  2. Stay hydrated. 
  3. Limit time outside.
  4. Stay active.
  5. Stay dry.
Credit: KENS
5 tips to stay warm and safe

Don't forget to protect outdoor pets, plants, and pipes during the colder months!

Stay weather aware by following the KENS 5 Weather Team:

Bill Taylor
Stacia Willson
Paul Mireles
Meagan Massey
Andrew Wilson
Jeremy Baker

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