La Niña translates from Spanish as "the girl-child". The term "La Niña" has recently become the conventional meteorological label for the opposite of the better known El Niño.

The term La Niña refers to the extensive cooling of the central and eastern Pacific Ocean. In Australia (particularly eastern Australia), La Niña events are associated with increased probability of wetter conditions.

Changes to the atmosphere and ocean circulation during La Niña events include:

• Cooler than normal ocean temperatures across the central and eastern tropical Pacific Ocean.
• Increased convection or cloudiness over tropical Australia, Papua New-Guinea, and Indonesia.
• Stronger than normal (easterly) trade winds across the Pacific Ocean (but not necessarily in the Australian region).
• High (positive) values of the SOI (Southern Oscillation Index).

A La Niña event is sometimes called an anti-ENSO (anti-El Niño-Southern Oscillation) event.