Jet streams are fast-flowing air currents found high in the atmosphere, typically at altitudes of about 30,000 feet. They form at the boundaries between different temperature zones, such as where warm air meets cold air. These winds can reach speeds of over 200 miles per hour and play a significant role in influencing weather patterns. There are two main types of jet streams: the polar jet stream and the subtropical jet stream. The polar jet stream is located near the poles and is associated with stormy weather, while the subtropical jet stream is found closer to the equator and generally brings clearer skies.