A stronger polar vortex is developing over the Arctic. Here's what it could mean for winter, including the role of a powerful El Niño.

Frigid temperatures are expected to impact much of the central and eastern United States in the coming weeks, including New York's Great Lakes region. The first of three polar vortex systems is ...

This winter, the Northern Hemisphere has been suffering from extreme cold. In South Korea, an unusually prolonged cold wave has continued even after the traditional coldest day of the year, Daehan ...