El Niño and La Niña are two sides of a natural climate pattern in the Pacific Ocean. They usually happen every few years and last around 9–12 months.

El Niño (Spanish for “Little Boy”) happens when the Pacific Ocean near South America gets unusually warm. This pushes the air currents and jet stream (a fast-moving ribbon of wind in the sky) southward. As a result, the U.S. Gulf Coast and Southeast get more rain and storms, while northern states and Canada turn warmer and drier. The warmer ocean also means fewer nutrients for fish, which can hurt fishing, while some warm-water species move in.

La Niña (“Little Girl”) is the opposite. The Pacific waters near South America turn cooler than normal, and strong winds push warm water westward. This brings up cold, nutrient-rich water that boosts sea life. On land, La Niña shifts the jet stream northward, making the southern U.S. drier, but the Pacific Northwest and Canada wetter. Winters become colder in the North and warmer in the South. It can also make hurricane seasons stronger.

Together, these ocean changes remind us how a single shift in the Pacific can ripple through weather, oceans, and economies worldwide.