Right now, the globe is in the grips of a La Niña, a weather phenomenon that occurs when a patch of the Pacific Ocean near the equator cools down below average.

Typically, La Niña means plenty of rain for the Pacific Northwest and a warm, dry winter for Southern California. That’s the pattern the National Oceanic and Atmospheric Administration, or NOAA, is predicting for this winter. However, this year’s La Niña is very weak compared to previous ones, said Bill Patzert, a climate scientist with NASA’s Jet Propulsion Laboratory.