El Niño is a climate pattern that describes the unusual warming of surface waters in the eastern tropical Pacific Ocean. El Nino is the “warm phase” of a larger phenomenon called the El Nino-Southern Oscillation (ENSO).

▪  El Nino and La Nina are complex weather patterns resulting from variations in ocean temperatures in the Equatorial Pacific Region. They are opposite phases of what is known as the El Nino-Southern Oscillation (ENSO) cycle.

o  The ENSO cycle describes the fluctuations in temperature between the ocean and atmosphere in the east-central Equatorial Pacific.

o  El Nino and La Nina episodes typically last nine to 12 months, but some prolonged events may last for years.

▪  El Nino is a climate pattern that describes the unusual warming of surface waters in the eastern tropical Pacific Ocean.

o  It is the “warm phase” of a larger phenomenon called the El Nino-Southern Oscillation (ENSO).

o  It occurs more frequently than in La Nina.

o  As El Nino brings rain to South America, it brings droughts to Indonesia, India and Australia.

▪  La Nina, the “cool phase” of ENSO, is a pattern that describes the unusual cooling of the tropical eastern Pacific.

o  La Nina events may last between one and three years, unlike El Nino, which usually lasts no more than a year.

o  Both phenomena tend to peak during the Northern Hemisphere winter.

o  It is beneficial for the Indian monsoon.