2025’s extreme weather had the jet stream’s fingerprints all over it, from flash floods to hurricanes |
The summer of 2025 brought unprecedented flash flooding across the U.S., with the central and eastern regions hit particularly hard. These storms claimed hundreds of lives across Texas, Kentucky and several other states and caused widespread destruction.
At the same time, every hurricane that formed, including the three powerful Category 5 storms, steered clear of the U.S. mainland.
Both scenarios were unusual – and they were largely directed by the polar jet stream.
Jet streams are narrow bands of high-speed winds in the upper troposphere, around four to eight miles (seven to 13 kilometers) above the surface of the Earth, flowing west to east around the entire planet. They form where strong temperature contrasts exist.
Each hemisphere hosts two primary jet streams:
The polar jet stream is typically found near 50 to 60 degrees latitude, across Canada in the Northern Hemisphere, where cold polar air meets warmer midlatitude air. It plays a major role in modulating weather systems in the midlatitudes, including the continental U.S. With winds up to 200 mph, it’s also the usual steering force that brings those