A dense fog advisory is in effect for the region until 7 a.m., according to the National Weather Service.
Foggy condition alerts are in place for the Benicia-Martinez, San Mateo-Hayward, Dumbarton, Carquinez, Richmond, Golden Gate and Bay bridges, according to the CHP.
Advisories were issued between midnight and 12:30 a.m.
Weather officials recorded visibility at less than a half mile in parts of the Bay Area.
According to the CHP, visibility on the Golden Gate Bridge is only one-tenth of a mile.