Temperatures remained high, but humidity levels were expected to soar as cool air moved in from the ocean and the Santa Ana winds retreated.
At the same time, the reversal of wind direction carried the risk of sending flames in new, dangerous directions.
“It could move just as quickly coming the other way,” said Bill Nash, a Ventura County fire spokesman.
The wind-whipped fire erupted on Thursday in the Camarillo area, threatening as many as 4,000 homes but only damaging 15, Nash said.
The blaze was only 10% contained yesterday, and the work of more than 900 firefighters, aided by air tankers, was just beginning.
The fire was 30km from Malibu, burning mostly in rugged mountains.
Fire crews have responded to more than 680 wildfires since the beginning of the year — some 200 more than average for the period.