It happens every year,,,our summer tourists get off the plane in San Mateo County at SFO and are confused by the nearby sign "South San Francisco, the industrial city" big on the hill, for a city with no self esteem or pride. They eventually get to SF, the other "sf" on the same peninsula, and are met by a solid wall of cloud at sea level with visibility usually less than 100 yards/meters,,,and they are SHOCKED !!
Why did our travel agent not tell us that Summer is reliably the worst weather of every year in San Francisco?!?! Winter has the clearest skies and is the off ,uncrowded, season,,,and Spring is lovely and also uncrowded,,,and sometimes in the Autumn the temperature will hit over 90F. (National Wx Service has only one wx station in the middle temp Mint Hill area,,,for a city with so many different climates and broad range of temperatures.) Why did all the travel guide books not tell us this ?!? Maybe they thought you would be driving inland away from the fog to fabulous Lake Tahoe or wonderful but roads in need of resurfacing Yosemite National Park,,,or downtown Fresno. OK, my bad joke with the 'fresno'.
It may burn off mid-day,,,or it might not, but you can expect fog so BAD on most summer days that you can NOT see the Golden Gate Bridge ,,,AT the Golden Gate Bridge south vista point right next to it! And forget about a view from the geographic center of the city at Twin Peaks, as it too is usually clouded over every morning , evening, and some/most mid-days.
Please folks, do not blame the most expensive city in the USA, SF,,, nor the people who actually LIKE the 'natural air conditioning' every Summer of the Fog ,,,who live in and work in the crazy careless everything-has-a-price, concierges gouge 30-40% usually or your ticket prices,,,city.
It is God's will, every year.