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 ...

(The Conversation) – Beach trips, cookouts and other outdoor activities are in full swing as summer heats up and the first widespread heat wave of 2025 arrives. For many people, summer is their ...