jet stream

American  

noun

1. strong, generally westerly winds concentrated in a relatively narrow and shallow stream in the upper troposphere of the earth.

2. similar strong winds in the atmosphere of another planet.

   jet streams on Jupiter.

3. the exhaust of a jet or rocket engine.

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jet stream British  

noun

1. meteorol a narrow belt of high-altitude winds (about 12 000 metres high) moving east at high speeds and having an important effect on frontogenesis

2. the jet of exhaust gases produced by a gas turbine, rocket motor, etc

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jet stream Scientific  

1. A narrow current of strong wind circling the Earth from west to east at altitudes of about 11 to 13 km (7 to 8 mi) above sea level. There are usually four distinct jet streams, two each in the Northern and Southern hemispheres. Jet stream wind speeds average 56 km (34 mi) per hour in the summer and 120 km (74 mi) in the winter. They are caused by significant differences in the temperatures of adjacent air masses. These differences occur where cold, polar air meets warmer, equatorial air, especially in the latitudes of the westerlies.

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jet stream Cultural  

1. A narrow band of swiftly moving air found at very high altitudes.

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Discover More

Movements of the jet stream have important (but generally short-lived) effects on weather patterns.

Travel time in an airplane can be lengthened or shortened by the jet stream, depending on the direction of flight and the strength of the stream.

Etymology

Origin of jet stream

First recorded in 1945–50

Example Sentences

One important effect is a shift in the jet stream, which influences the paths of storms.

From Science Daily • Jun. 15, 2026

“We were standing in the jet stream, on the edge of space,” Whittaker wrote in his 1999 memoir, “A Life on the Edge.”

From Los Angeles Times • Apr. 8, 2026

"Just as small shifts in the jet stream can change the weather, small changes in these cellular winds could change how diseases begin or progress," Cathy said.

From Science Daily • Apr. 1, 2026

Racing across the Atlantic with wind speeds more than 200mph, the powerful jet stream has helped develop a deep area of low pressure currently sitting near to Iceland.

From BBC • Mar. 12, 2026

But in early May, we hoped, the approach of the monsoon from the Bay of Bengal would force the jet stream north into Tibet.

From "Into Thin Air" by Jon Krakauer