Is an abnormal weather pattern caused by the warming of the Pacific Ocean near the equator, off the coast of South America. The sun warms the water near the equator, which can make more clouds and, therefore, more rain. However, normally there are trade winds, which blow that warm water west. During El Niño, those trade winds weaken, or even reverse, which lets the warm water that is usually found in the western Pacific remain or flow east. This warm water displaces the cooler water that is normally found near the surface of the eastern Pacific, setting off atmospheric changes that affect weather patterns in many parts of the world.