ENSO

El Niño Southern Oscilation (acronym:«ENSO») is an irregular periodic variation in winds and sea surface temperature over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics. The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña

When the ONI exceeeds 0.5C° for at least five consecutive months, the corresponding year is considered to be an El Niño year