Normally, strong winds blow across the tropical Pacific, moving west. They push warm water toward Asia and Australia. Meanwhile, cool water rises to the surface on the west coast of South America. This is called “upwelling.”

That cold water is full of food for itty-bitty organisms called phytoplankton. Phytoplankton gobbles the nutrients. Then fish and other animals eat the phytoplankton.

Meanwhile, the warm Pacific water gets sucked up into clouds. It rains down on Indonesia and New Guinea. The cool air on the other side of the ocean keeps South America drier than usual.

But El Niño puts everything in reverse. That western wind grows weak. Warm waters don’t blow west. Upwelling doesn’t happen normally. Phytoplankton don’t get fed, which means fish go hungry. Warm surface waters cause more rain near Ecuador, Chile, and Peru. Coasts flood. Indonesia and Australia dry out. Everything is backward!

When El Niño shows up, weather gets wild. Will this “little boy” give you a year of beautiful skies? Or will he burn up your crops and then knock down your shed with a hurricane? It all depends on where you live.

El Niño might ruin harvests in Southern Africa. He might dry out Australia so much it crackles with wildfires. On the other hand, he might soak Argentina and Chile with rain. Over the Atlantic, he might break up hurricanes. But in the eastern Pacific, he might cause more storms. His warm waters can harm coral reefs. But if you live in the middle of the United States, El Niño’s warmth might mean a big, fat, juicy corn crop.