Fog City Blues
The San Francisco Fog
The fog of San Francisco Bay is a specific type of fog. It is a sea fog identified as advection fog, which is characterized by the lateral transfer of temperature by wind blowing over cooler water. In circumstances such as these, often, the water is cool enough to lower the temperature of the air to the dewpoint, causing fog generation. Coastal areas having Mediterranean climates, such as that of San Francisco, have especially frequent sea fog blowing off the ocean to just a few miles inland. Once the fog has been generated as such, heated air in California’s Central Valley lowers the air pressure, causing the relatively higher pressure air out at sea to force the fog inland into the San Francisco Bay Area.
San Francisco’s fog is created when warm, moist air blows from the central Pacific Ocean across the cold waters of the California Current, which flows just off the coast, creating a cool, moist wind.
San Francisco is called The Naturally Air Conditioned City because of the frequent fogs that roll in from the Pacific Ocean, especially during the summer.
The San Francisco fog hides things. That can be either good or bad. Sometimes it hides people who don’t want to be found, but, more often, it hides the activities of the different players in the city, both mortal and supernatural. It’s not uncommon to see the Summer and Winter fae duking it out on a San Francisco street when the fog rolls in in the evening. And it’s far too often that when the fog burns off midmorning, it uncovers the ugliness left behind in the wake of the cities power struggles.