Millions of Americans across 22 states have been urged to stay out of the sun today as heat index temperatures for almost half the country soar into the triple digits.

A heat advisory is in effect in Boston and several other Massachusetts communities through 7 p.m. on July 17. The National Weather Service warned of "dangerous heat and humidity" with heat indices ...

New York City remains under a heat advisory Thursday, as high temperatures hit the 90s and feel more like triple digits. The ...

Yahoo News used data from the National Oceanic and Atmospheric Administration to calculate the number of days in each county ...