Why do El Niño and La Niña change weather around the world?
Quick Answer
They shift sea-surface temperatures and atmospheric circulation across the tropical Pacific, which alters rainfall, storms, and jet stream patterns globally. These changes are part of the El Niño–Southern Oscillation.
The Full Story
El Niño and La Niña are opposite phases of a coupled ocean-atmosphere system in the tropical Pacific. During El Niño, warmer-than-average waters often weaken the normal trade winds and shift convection eastward, changing rainfall patterns far from the Pacific. La Niña usually strengthens the opposite pattern, often with cooler waters in the eastern Pacific and different storm tracks. These events can affect floods, droughts, hurricanes, and winter weather in many regions, including North and South America, Australia, and parts of Africa.
Key Facts
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