The jet streams above Earth are always blowing, and they have a big effect on the weather. In this lesson, you’ll learn what jet streams are, what they do, and why jets love to fly in them.
What is a Jet Stream?
What do you call a stream that’s found six miles above the ground and has no water? The answer is a jet stream. A jet stream is a band of wind that’s high up in the atmosphere. The atmosphere, which you might think of as the air, is actually the collection of gases that surround the Earth.
A jet stream moves fast, like a jet airplane, with wind speeds usually between 120 and 250 miles per hour, which means if you put a balloon in a jet stream, it could fly the distance between Washington, D.C., and New York City in about one hour.
Jet streams form at the boundaries between hot and cold air masses.
A jet stream can be thousands of miles long and a couple of hundred miles across, but you don’t feel a jet stream because it’s high up in the sky. Jet streams are found about six to nine miles above the Earth. Airplanes fly at about that same height, so a jet can fly in a jet stream. In fact, when an airplane is flying in the same direction as the stream of air, it can travel very fast and use up less fuel.
There are different jet streams found around the world, but the primary ones are the polar jet streams and subtropical jet streams. These jet streams are found in both the northern and southern hemispheres.