The National Weather Service scheduled a dense fog advisory to take effect at 10 p.m. and extend through 9 a.m. Sunday.
The shallow marine layer will usher in the fog, which could cause visibility to drop to less than a quarter-mile in higher coastal terrain, including on the mesas and in some coastal valley areas, forecasters said.
Forecasters said the fog could impact drivers along portions of Interstates 8, 15 and 805, and state Routes 52 and 78.
Drivers were advised to slow down, use their low beam headlights and leave distance ahead of them.
Flight delays could also be possible at coastal airports Sunday morning, forecasters said.