"Climate change is driving both wet and dry extremes," NOAA Administrator Rick Spinrad said in a statement.
"We're not calling for catastrophic and major widespread flooding," said Ed Clark, director of NOAA's National Water Center.
California's winter was marked by a punishing succession of so-called atmospheric river storms, the product of vast, dense airborne currents of water vapor funneled in from the tropical Pacific.
The storms have unleashed widespread flooding, mudslides, power outages, fallen trees, surf damage, road wash-outs and evacuations since late December.
"Winter precipitation, combined with recent storms, wiped out exceptional and extreme drought in California for the first time since 2020, and is expected to further improve drought conditions this spring," NOAA said.