How Does the Jet Stream Change through the Year?
ES1906  Great Rivers of Air

Jet streams are narrow bands of high-speed winds that move like great rivers of air around Earth in each hemisphere. These rivers of air are located between 8 to 12 miles (13 to 19 km) above Earth's surface, and generally flow from west to east at mid-latitudes. Wind speeds within jet streams reach as high as 250 miles per hour (400 km/hr).

National Weather Service
Generalized view of the polar jet stream flowing across North America.
Notice that the fastest wind speeds tend to be in the middle of the jet stream.

 Step:   1   2   3   4   5   6