What Are The Polar Jet Stream And Vortex?

Written By Teacher: Elizabeth Ward

My name is Elizabeth Ward. I am a former Early Childhood, Elementary, and English as a Foreign Language educator. I have taught third grade Science and Social Studies as well as Kindergarten in both urban and rural Oklahoma public schools. I taught online EFL to students of all ages in China for four years. I also have experience in curriculum development and content design for teachers in the physical and digital classroom. As a former teacher I have a passion for supporting teachers and making their jobs easier. I currently live in the greater Houston area with my husband and four dogs. 

The polar jet stream and polar vortex play key roles in shaping weather patterns, but their behavior is changing as the climate warms. Understanding how these atmospheric systems interact helps students connect climate change to extreme weather events. This topic encourages discussions about the science behind shifting weather patterns and the consequences for different regions. Understanding weather patterns can start as early as Kindergarten! Check out this lesson all about weather, designed for Kindergarten through second-grade. Older students can learn about the differences between weather and climate with this lesson from CLEAN.

Written By: MIT Environmental Solutions Initiative

The MIT Climate Change Engagement Program, a part of MIT Climate HQ, provides the public with nonpartisan, easy-to-understand, and scientifically-grounded information on climate change and its solutions.

The polar jet stream and polar vortex are two rings of fast-moving air around the Arctic, which play a large role in world weather patterns. Many climate scientists believe that global warming is changing these rings, in ways that allow freezing air from the Arctic to intrude on the warmer mid-latitude regions. This means that, even as the Earth warms on average, climate change may lead some places to see more extreme cold spells during winter.

These more frequent extreme weather events pose challenges to protect people and infrastructure from freezing.

The polar jet stream sits in the troposphere, the lowest layer of our atmosphere where most weather happens. It is characterized by a belt of wind that blows from west to east at speeds up to a couple of hundred miles per hour. While it shifts a bit north or south throughout the year, it usually stays between the 50th and 60th parallels: roughly between the Great Lakes and Canada’s northern territories, or between France and Norway. The jet stream forms at the boundary where cold polar air and warm mid-latitude air try to mix, creating fast-moving waves and eddies. 

The polar vortex is higher than the polar jet stream, in the stratosphere up to 30 miles above the Earth. It is also further north, sitting over the North Pole. Scientists are still working to fully understand the polar vortex: continuous long-term observations are only available after the satellite era, and many climate models struggle to simulate it. But some climate scientists believe that it, too, is changing in ways that affect weather further south.