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What is a “dry heat” and is it actually cooler than humidity?

Posted at 10:40 AM, Jul 17, 2019

PHOENIX — This Arizona summer heat is no joke. So far this year we've reached high temperatures in Phoenix as warm as 115 degrees. BUT, the heat index “feels like” temperature was only 108 degrees that day in July. So why is that?

According to chief meteorologist Amber Sullins, once the summer heat reaches a certain high temperature, if the air is dry enough, there’s a tipping point where the heat index begins to feel cooler than the actual temperature outside.

Here's how Amber explains it:

"Our bodies cool off through the evaporation of sweat. When it's humid outside, it's harder to cool off because our sweat evaporates slower. That's where the idea of the heat index comes from. It takes into account the temperature and humidity and calculates a "feels like" temperature that is often hotter than the actual air temperature. But, when it's super dry out you can get a "feels like" temperature that is lower than the actual air temperature."

Here is the chart that shows how a "feel like" temperature is calculated, based on the high temperature and humidity.

On a day where Phoenix hit 115 degrees, the humidity was at only 8 percent. That put our "feels like" temperature at 108 degrees.

So, it’s up to you to decide. Would you prefer 89 degrees with 60 percent humidity and a “feels like” temperature of 102 like it is in Chicago? Or 115 degrees with 8 percent humidity and a “feels like” temperature of 108 like we had earlier this month?

Let us know by commenting on the post below!