At an altitude above 20,000 feet, or between six and nine miles above the Earth's surface, the jet stream winds make their presence known.This puts the jet stream near the top of the Earth's troposphere, where most of the Earth's weather occurs.he wind generated at polar fronts helps to power polar-front jet streams. tropopauseâ The zone in the atmosphere that divides the troposphere and the stratosphere. The altitude of the tropopause varies with latitude, being highest above the equator (about 12 miles) and lowest near the poles (less than five miles).