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 ...

The heat index is a measure of how hot it really feels on your body when relative humidity is factored in with the actual air temperature. Since heat index values were devised for shady, light wind ...

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 ...

"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. Also known as the apparent temperature, the heat index is a number ...

Temperature is one of the primary factors in every weather forecast, but when we get into the dog days of summer, it’s just not that simple. We have to use something called the “heat index” to ...