What are El Niño and La Niña?(opens in new tab)

What is El Niño?

• Ocean Temperature: Surface waters in the central and eastern equatorial Pacific become much warmer than average.
• Winds: Trade winds (winds blowing east to west) weaken or even reverse.
• Weather Effects: Warm water moves east, bringing heavy rain to South America and causing drought in Australia and Southeast Asia. In the U.S., winters are often warmer and drier in the North and wetter in the South.

What is La Niña?

• Ocean Temperature: Surface waters in the same region become cooler than average.
• Winds: Trade winds become much stronger than normal.
• Weather Effects: Warm water piles up near Asia. This brings more rain to Indonesia and drier conditions to the southern U.S. Winters tend to be cooler in the U.S. Northwest and warmer in the Southeast