A state of emergency was declared in northern areas after mass evacuations, with 1,500 properties destroyed.
About 20,000 people fled from Napa, Sonoma and Yuba counties in response to some the state's worst-ever wildfires.
Such fires are more common in southern California but a combination of dry weather and strong winds has fuelled the destruction in the north.
"These fires have destroyed structures and continue to threaten thousands of homes, necessitating the evacuation of thousands of residents," Governor Jerry Brown said, declaring the emergency.
There is little sign the weather in the coming days will bring relief to firefighters, BBC Weather says. More tinder dry conditions are forecast, with no rain expected.