A National Weather Service meteorologist said winds were not expected to be as strong as they had been, welcome news for firefighting crews.
Strong Santa Ana winds Thursday had spread an early morning illegal campfire into a major conflagration by mid-morning, officials said.
Three men, all in their 20s, were arrested Thursday and charged with starting the fire.
Glendora Police Chief Tim Staab said the men threw paper onto a fire started in an area not designated for camping. A gust of wind then blew embers "all over the place," the chief said.
About 700 firefighters from the Los Angeles County Fire Department, the U.S. Forest Service and other agencies reported the so-called Colby fire 30 percent contained Thursday night, the Los Angeles Times reported.
Thousands of people within the evacuation area were allowed to return to their homes after winds died down and firefighters announced "the forward spread of the fire has stopped."
Temperatures in the area were expected to be above 80 degrees with less than 10 percent humidity.