I made it to the top of Twin Peaks on a foggy morning and had terrific views of the city.
North towards the Golden Gate Bridge:
San Francisco under fog cover.
South towards the San Bruno Mountains:
Looking south from Twin Peaks, fog blanketing the city.
And luckily I encountered another fog bow, as these next three photos show:
Fog bow on Twin Peaks
Fog bow on Twin Peaks
Fog bow on Twin Peaks