"Motorists should be alert for slick roadways due to the combination of oil and rainfall," the National Weather Service warned.
Friday's rain was the result of a cold front that was expected to weaken as it moves south, the NWS said. It expects to see stronger rainfall late Saturday morning because of a second cold front that also will trigger showers through the evening.
A weak third cold front on Sunday is not expected to generate rain around the Los Angeles area, forecasters said.
Precipitation totals resulting from the three cold fronts should range from between a tenth and a half-inch of rain, with the higher amounts expected in Santa Barbara and San Luis Obispo counties.
Forecasters said sunny weather will return Tuesday, when the high should be 72 in downtown L.A.