Millions of people across the United States have been issued safety warnings amid concerns over very high temperatures.

TONIGHT: A spotty storm possible through sunset, though chances are low at 20%. Warm and muggy 80s.

NYC faces another excessive heat warning Tuesday, while parts of Long Island and New Jersey are under a heat advisory.

As a heat wave hits multiple U.S. states, some areas are have been placed under extreme heat watches and warnings.

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

When there is an extreme heat warning, it’s recommended that you avoid strenuous outdoor activities if possible and to drink extra water and take frequent breaks if you must work outside.