Basically, when the body sweats, the perspiration evaporates, cooling the body. When the humidity is high, the sweat doesn't ...

The National Weather Service has issued an extreme heat warning for Lower Hudson Valley, with a heat index of up to 107 for second consecutive day.

The National Weather Service issued an extreme heat warning for a second day as the heat index surpasses 100. See how hot it will get in Delaware.

In major cities such as Washington, D.C., Baltimore, Philadelphia and New York, the temperature was forecast to approach 100 ...

It'll be very hot, but what conditions are required for the extreme heat warning that much of New Hampshire is under? Matt Hoenig breaks it all down.

While the rest of this week will feel stiflingly hot, temperatures are not expected to reach the highs required for an excessive heat warning.

NYC is under an excessive heat warning​ today, while Long Island and the Jersey coastline are under a heat advisory.

Extreme heat is impacting states across the country. See maps of high temperature forecasts and heat index levels.

An excessive heat warning has been issued for the Hudson Valley through Tuesday at 8 p.m., according to the National Weather Service. The combination of temperatures in the 90s and dew points in the ...

The Washington Monument is closed on Monday after an excessive heat warning was issued for the Washington D.C. area.

With a heat wave causing excessive heat warnings in Delaware, you'll hear a lot about the heat index this week. What to know ...