As the U.S. prepares to take on another bout of cold weather, the term "polar vortex" is getting thrown around. But what is ...

WASHINGTON (AP) — Warm Arctic waters and cold continental land are combining to stretch the dreaded polar vortex in a way ...

A polar vortex brings bitterly cold Arctic air into southern Ontario. Here’s what it is and what you can expect.

The big winter (and popular) topic is dusted off very early this season as frigid air plunges south next weekend. But what is ...

Starting Thursday, dangerously frigid air from Siberia and the North Pole is forecast to plunge the Great Lakes region into ...

What is the polar vortex? This article explains what a polar vortex is in simple terms, how it influences winter weather in ...

Major cities across the Northeast and Midwest are facing temperatures 10-20 degrees below average, according to forecasters.

After this weekend's snow storm moves out, cold Arctic air will move in.

A warming Arctic set the stage for a massive winter storm expected to stretch 2,000 miles across the Eastern U.S. this weekend.

Colder air is becoming re-established in the central and eastern United States after a recent warmup. Over the next 10-14 ...

No weather records are expected to be broken. The coldest Jan. 24 on record was -32.2 C in 1882, according to historical data ...

Jupiter and Saturn's different polar storms reveal clues about planet interiors: Saturn has harder bottom than Jupiter.