El Nino is the name given to an abnormal weather pattern caused by the warming of the Pacific Ocean near the equator, just off the coast of South America. The sun warms the water near the equator, which creates more cloud and consequentially, more rain. Normally there are trade winds which blow the warm water west, but during El Nino, those winds weaken or even reverse, which lets the warm water normally found in the western Pacific remain or flow east.