Add Yahoo as a preferred source to see more of our stories on Google. "It's not the heat, it's the humidity." Actually, it's both, and that's where the National Weather Service's heat index comes in.

The heat index, or apparent temperature, combines air temperature and humidity to indicate how hot it feels to the body. High humidity slows sweating, the body's natural cooling system, making ...

Hundreds of people working or playing outside – even those who seem healthy – succumb to heat-related illnesses each year.

Each week, our meteorologists answer a question from readers.

Heat advisories have been issued for various parts of Florida, urging residents to take precautions. Dangerous heat is expected on Florida's Treasure Coast, with predicted heat index values from 109 ...

Florida is under a heat advisory with dangerous heat index values expected to reach 110-115 degrees. This heat wave coincides with the one-year anniversary of the hottest day on record for Earth. The ...

FIRST ALERT WEATHER. SO WE GOT A MIXED BAG OF THINGS COMING. IMPACT ALERT KIND OF ESCALATED QUICKLY. IT DID. YEAH. YOU KNOW SO WE HAVE SOME ALERT DAYS BECAUSE OF THE HEAT. YOU KNOW, JUST TOMORROW’S ...

Heat advisories have been issued across Florida, with heat index values expected to reach 110-115 degrees. The heat dome affecting the South may cause record high temperatures in the Southeast. Heat ...