A state of unusually cool sea surface temperatures in the western Pacific, which are associated with lowered precipitation in the southern USA and western South America, but an increase in the frequency of tropical cyclones in the Atlantic, and heavier rainfall in Indonesia and Australia. La Niña can be seen as the other extreme from El Niño.

‘There is strong statistical and modelled evidence that persistent, La Niña-like, cooler sea surface temperatures…produce multiyear droughts not only in the Great Plains and the Southwest, but also in the Mediterranean region of Europe, the Pampas region of South America, the steppes of Central Asia, and the outback of Western Australia’ (Goodrich (2007) Geog. Compass 1).