<P> La Niña (/ lɑːˈniːnjə /, Spanish pronunciation: (la ˈniɲa)) is a coupled ocean - atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño--Southern Oscillation climate pattern . The name La Niña originates from Spanish, meaning "the little girl", analogous to El Niño meaning "the little boy". It has also in the past been called anti-El Niño, and El Viejo (meaning "the old man"). During a period of La Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3 to 5 ° C. In the United States, an appearance of La Niña persists for at least five months . It has extensive effects on the weather in North America, even affecting the Atlantic and Pacific hurricane seasons . </P> <P> La Niña is the positive phase of the El Niño Southern Oscillation and is associated with cooler - than - average sea surface temperatures in the central and eastern tropical Pacific Ocean . However, each country and island nation has a different threshold for what constitutes a La Niña event, which is tailored to their specific interests . For example, the Australian Bureau of Meteorology looks at the trade winds, SOI, weather models and sea surface temperatures in the Niño 3 and 3.4 regions before declaring that a La Niña event has started . However, the Japan Meteorological Agency declares that a La Niña event has started when the average five - month sea surface temperature deviation for the NINO. 3 region is more than 0.5 ° C (0.90 ° F) cooler for 6 consecutive months or longer . </P> <P> A timeline of all La Niña episodes between 1900 and 2017 . </P>

What happens in the pacific ocean during a la nina event
find me the text answering this question