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 ...

Each week, our meteorologists answer a question from readers.

What does the "heat index" mean and how does it apply to people? -- S.S., Tulsa. The World Almanac and Book of Facts, updated annually, always includes the heat index ...

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 ...

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 ...