The polar jet stream is a fast-flowing river of air high in the atmosphere, typically found at altitudes of about 30,000 feet. It forms at the boundary between cold polar air and warmer air from the mid-latitudes. This jet stream plays a crucial role in influencing weather patterns, as it helps to steer storms and can affect temperatures across different regions. The strength and position of the polar jet stream can change with the seasons, often shifting southward in winter and northward in summer. Variations in the jet stream can lead to extreme weather events, such as blizzards, heatwaves, and torrential rain, impacting daily life and ecosystems.