The El Niño-Southern Oscillation (ENSO) cycle is a recurring climate pattern pertaining to changes in the water temperatures out in the central and eastern tropical Pacific Ocean, according to the weather service.

It is just the start of 2025, but the U.S. is already seeing extreme weather across the country, from the wildfires raging in southern California to the uncharacteristically heavy snow in the Southeast and it seems that the return of La Niña may be responsible for some of it.

The National Oceanic and Atmosphere Administration announced this week La Niña has arrived. This usually means the northern parts of California and the U.S. see more rainfalls where as Southern California sees less rain.