The Pacific is the biggest ocean on Earth. Every few years, its winds get weaker. Then warm water spreads across it, all the way to South America.
Scientists call this El Niño. The name means "the boy" in Spanish.
Scientists check the water's temperature every day. In 2015 there was a very strong El Niño. This one is on track to be even stronger, the strongest ever measured.
They think the ocean will stay extra warm until February.