The wet, chilly weather slowed the march of the blaze, which has scorched more than 90,000 acres, destroyed about 850 homes and killed four people.
"Things are looking better," U.S. Forest Service spokeswoman Tricia Abbas said.
Crews also worked to remove debris and clear roads for the eventual return of the 15,000 people who were evacuated earlier this week. Firefighters burned piles of dead trees and dry brush near the small community of Sugarloaf.
"With this inclement weather, they feel they can burn that stuff safely, which will provide increased fire safety for communities later on this week when the wind and weather conditions are expected to change," said Ann Westling, a Forest Service spokeswoman.
There was a negative side to the snow and rain that fell overnight Friday. The precipitation caused a mud and rock slide that closed Highway 18, a major road in the area. A number of trees also fell after being weakened by fire and a previous infestation of bark beetles.
"We've got trees coming down like dominoes," Forest Service spokesman Steve Ritchie said. "They're coming down on the roads all over the place."
The fire was 45 percent contained after moving within eight miles of Big Bear Lake. Seventeen miles to the west, residents were allowed to return to several communities near Lake Arrowhead, an area threatened by the fire earlier in the week.
The blaze was among a barrage of wildfires that have killed 20 people, destroyed more than 3,300 homes and burned about 750,000 acres across Southern California over the past week.
Six fires were still burning across four counties Saturday. The most destructive and deadly blaze, a 281,000-acre fire in the mountains northeast of San Diego, has become the largest individual wildfire in California history. It was 81 percent contained Saturday.
CBS News Reporter Stephan Kaufman says full containment of the Cedar blaze could come by Monday, two days ahead of earlier estimates.
A multi-agency fact-finding team has been formed to investigate the initial efforts to battle the blaze. A San Diego County Sheriff's helicopter pilot said he spotted the fire when it was still fairly small Oct. 25 and called for air-tankers. But he said state firefighters rejected the request because it came minutes after such flights had been grounded for the night.
In San Diego County, firefighters said the threat had eased in Julian, known for its vineyards and apple orchards. The blaze was expected to burn east into sparsely populated mountain and desert areas.
The blazes have made 2003 California's most destructive wildfire year ever, with a total of 4,443 homes destroyed across the state, according to Karen Terrill, a spokeswoman for the California Department of Forestry.
Forecasters said the heat and dry Santa Ana desert winds that whipped the flames into infernos could return early next week.
People displaced by the wildfires took time to celebrate Halloween at evacuation and disaster relief centers. Hundreds of children in a San Bernardino International Airport hangar donned donated costumes and munched candy.
Volunteers painted faces of children, who ate meals and candy on green cots covered with blankets.
Saturday, Homeland Security Secretary Tom Ridge toured a relief center in Claremont and said he was unsure if the nation had ever seen such a destructive wildfire.
"We have our work cut out for us," Ridge said.