The effects of each La Niña event vary depending on the intensity, duration, time of year when it develops, and the interaction with other modes of climate variability.
La Niña refers to the large-scale cooling of the ocean surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation, namely winds, pressure and rainfall. The effects of each La Niña event vary depending on the intensity, duration, time of year when it develops, and the interaction with other modes of climate variability.  In many locations, especially in the tropics, La Niña produces the opposite climate impacts to El Niño.