A polar vortex, more formally a circumpolar vortex, is a large region of cold, rotating air; polar vortices encircle both of Earth's polar regions. Polar vortices also exist on other rotating, low-obliquity planetary bodies.

The term polar vortex can be used to describe two distinct phenomena; the stratospheric polar vortex, and the tropospheric polar vortex. The stratospheric and tropospheric polar vortices both rotate in the direction of the Earth's spin, but they are distinct phenomena that have different sizes, structures, seasonal cycles, and impacts on weather. Read more...

Polar vortex patterns explain shifting US winter cold despite warming climate   PhysOrg - July 11, 2025

Despite a warming climate, bone-chilling winter cold can grip parts of the U.S. In a study appearing in Science Advances, researchers found that two specific patterns in the polar vortex, a swirling mass of cold air high in the stratosphere, steer extreme cold to different regions of the country. One pattern drives Arctic air into the Northwest U.S., the other into the Central and Eastern areas.

The Polar Vortex Has Shifted Into Reverse - And Is Now Spinning Backwards   Science Alert - April 5, 2024

A major current of circulating air called the Arctic polar vortex has completely reversed course and is now spinning 'backwards'. With winds now blowing easterly, scientists are trying to predict what effect this might have on weather systems in the coming months.