Sorry this is long, it’s the best I’ve got. The name was chosen based on the time of year (around December) during which these warm waters events tended to occur. The term El Niño refers to the large-scale ocean-atmosphere climate interaction linked to a periodic warming in sea surface temperatures across the central and east-central Equatorial Pacific. The term El Niño refers to the large-scale ocean-atmosphere climate interaction linked to a periodic warming in sea surface temperatures across the central and east-central Equatorial Pacific. The vast tropical Pacific Ocean receives more sunlight than any other region on Earth. Much of this sunlight is stored in the ocean in the form of heat. During an El Niño water temperatures in the Pacific Ocean may rise on average 3 - 5 degrees above average