A “Low Fog Event” or LFE as its often referred to in the San Francisco photography community is when the fog is laying so low around the Golden Gate Bridge that you can see the top of the bridge towers peaking out above it. If you live in northern part of San Francisco you can often hear the fog horns droning which is a great indicator of a LFE. When this happens you the best place to go is to the Marin Headlands on the North West side of The Golden Gate Bridge. You will find dozens of photographers set up all over the headlands, prime spots include Hawk Hill Parking Area and Slacker Hill (requires a steep on foot climb).
Here are some photos I have captured over the years of living in San Francisco.
Taken in the Marin Headlands
Taken from Twin Peaks