The warning was expected to be in effect until 8 p.m. for the Antelope Valley and until 11 p.m. for the Apple Valley and Lucerne Valley, as well as the mountains in San Bernardino and Riverside counties.
Southern California received half the normal amount of rainfall this winter, which means there is a lot of dry brush. The combination of strong winds, high temperatures and low humidity levels has put fire officials on alert. They say this summer will be warmer and drier than last year.
The L.A. County Fire Department has extra personnel on duty in northern L.A. County as long as the red-flag warning is in effect.
"This year, the rainfall has been below normal, so we have the dead fuel from last year and we have the dead fuel from this year," said Los Angeles County Fire Chief Daryl Osby.
Local agencies, the U.S. Forest Service and Cal Fire said they will pool their resources to attack wildfires. Authorities warned residents in fire-prone areas to make sure they create at least 100 feet of defensible space around their homes.
Two fires that started over the weekend in the Inland Empire have been fully contained. The blaze in Beaumont charred 2,200 acres, and the one in Cabazon burned 367 acres. No homes were lost. The cause of the fires remains under investigation.
Fire officials say 90 percent of wildfires in the area are started by people, not the weather. Officials reminded the public to be extremely careful when working outdoors with machinery.