La Niña is sort of the opposite of El Niño.
It refers to the periodic cooling of ocean surface temperatures in the central and east-central equatorial Pacific that occurs every 3 to 5 years or so.
La Niña represents the cool phase of the El Niño or Southern Oscillation (ENSO) cycle, and is sometimes referred to as a Pacific cold episode.
La Niña originally referred to an annual cooling of ocean waters off the west coast of Peru and Ecuador.
This, too, affects weather around the globe and in the U.S.
According to scientists, La Niña cycles generally create a more active hurricane season in the Atlantic.