Jet streams are slim strips of strong winds that have a big influence on small aircraft and climate. They can affect weather conditions and push air masses around. In the US, jet streams typically run from west to east.
Where to Find Them
Found in the troposphere, jet streams sit at about 7 miles above the Earth’s surface. Though the streams are fairly narrow, it’s not unusual for them to span thousands of miles long over continents and oceans.
Jet streams form a wall between hot and cold air. This means that jet streams are more active during different seasons of the year. The most common season to encounter these streams are during the winter months when the North is colder than usual.
The temperature plays a big role in the severity of the jet stream. If the difference between the hot and cold air is high, the jet stream will run fast and reach speeds of up to 250 mph or greater. This can be challenging for small aircraft; however, the average speed of a jet stream is only 110 mph.
The Northern & Southern Hemispheres
Both hemispheres contain two different kinds of jet streams: polar and subtropical. The more active jet streams, however, are found in the Northern hemisphere. While these are the two most common streams, there are others that can form when high wind speeds occur.