The warnings were issued Saturday for Los Angeles and Ventura counties, the Los Angeles Times reported.
Red-flag warning are issued when winds reach about 25 mph with gusts of more than 35 mph and there is a relative humidity of under 15 percent, said Scott Sukup, a meteorologist for the National Weather Service in Oxnard.
"It's going to be pretty breezy," Sukup said, predicting winds of 15 to 25 mph with gusts up to 40 mph. "It's also going to be very dry because we have these offshore Santa Ana winds."
Red-flag warnings may be issued for mountain and foothill areas in San Diego, Riverside, Orange and San Bernardino counties Sunday night.
"It's quite dry in the mountains as far as the fuels are concerned. They are in critical condition," said Robert Balfour, a senior forecaster for the National Weather Service in San Diego. "The relative humidity right now in the mountains is already below 15 percent, but we don't have the winds blowing yet."