Jet Stream vs. Gulf Stream: What’s the Difference?

In January 2025, New Orleans awoke to the surreal sight of snow blanketing Bourbon Street and the French Quarter for the first time in decades. The Deep South of the United States was hit with a rare snowstorm, the result of a collision of air pressure systems moved by jet streams toward the Gulf of Mexico.

“Wait,” you might be thinking—”wouldn’t it be the Gulf Stream that affects the Gulf of Mexico?” Now might be a good time for a primer on these two climate systems that are the underlying causes of weather events in the region. Let’s dive into the difference between jet streams and the Gulf Stream.

1. What Is a Jet Stream?
2. What is the Gulf Stream?

What Is a Jet Stream?

Jet streams are air currents formed by the collision of warm tropical air and cold polar air in the atmosphere, plus the rotation of the planet. When meteorologists in North America mention “the jet stream,” they are usually referring to the Polar Jet Stream, which circles Earth between the latitudes of 50° and 60° North (there’s also one in the same latitudes in the Southern Hemisphere). The Subtropical Jet Streams occur around 30° North and around 30° South.

These streams form because Earth is not evenly heated. Solar heat is focused on the tropics. The resulting hot air is more buoyant and rises towards either the north or south pole and the meeting of the warm and cold forms a jet stream. 

Their movements are choreographed by the rotation of the planet, which pushes the streams in a west-to-east rotation. The result is a cycle of strong winds circling both poles in the highest altitudes of Earth’s atmosphere.

The streams’ locations can shift due to several factors. The most predictable is seasonal. In the spring, jet streams move towards a polar vortex, helping to contain cold air in the polar regions. In the fall, they move towards the equator and bring that cold air down with them.

Storm systems and other weather phenomena get caught up in jet streams and are taken along their path, sometimes to unusual effects. In the case of the snowstorm that barreled through the southeastern U.S., the Polar Jet Stream picked up a cold, high-pressure air system from the Rockies and pulled up moisture from the Gulf of Mexico, resulting in intense snowfall.

What is the Gulf Stream?

While jet streams are air patterns, the Gulf Stream is an ocean pattern that also has an impact on weather. 

The Gulf Stream is a strong current that brings warm water from the Gulf of Mexico, distributes it along the East Coast of the U.S., and flows across the Atlantic, all the way to the Norwegian Sea. The British Isles and Iceland would be as cold as northern Canada without it, and Boston and New York winters even more miserable.

The Spanish explorer Juan Ponce de León was the first European to observe the ocean pattern in 1513, and colonizing ships often used it to hitch a ride back to Europe.

But its effects are not universally convenient. Warm water dissipates into the atmosphere faster, causing more rain and snow, and warm water strengthens hurricanes. 

This is why climate scientists are concerned about a rise in the temperature of the Gulf Stream that exceeds the average increase in oceans. The current’s temp has increased by 1.8°F over the last 20 years. But another global warming-related concern might prove more serious: An influx of fresh water from Greenland’s melting ice sheet could lead to a shutdown of the system of currents (called the Atlantic Meridional Overturning Circulation, or AMOC) that feeds the Gulf Stream for the first time since the last Ice Age. Its collapse could result in temperature drops in Western Europe, flooding in North America, and less precipitation for the Amazon’s rainforests.

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