El Ni簽o and La Ni簽a are the opposite phases of ENSO, which is short for El Ni簽o-Southern Oscillation. Operating in the tropical Pacific Ocean, ENSO is Earth's singlest most influential natural climate pattern. El Ni簽o and La Ni簽a alternately warm and cool large areas of the tropical Pacific - the world's largest ocean - which significantly influences where and how much it rains there. The primary location of moist, rising air is centered over the central or eastern Pacific during El Ni簽o and over Indonesia and the western Pacific during La Ni簽a. Like a boulder in a stream, this relocation disrupts the atmospheric circulation patterns that connect the tropics with the middle latitudes, which in turn modifies the mid-latitude jet streams. By modifying the jet streams, ENSO can affect temperature and precipitation across the United States and other parts of the world.