The low cloud formation, known as tule fog, first formed over central California in November and persisted into early December. The Central Valley typically sees this type of fog during the colder months of the year, when the air near the ground is cold and moist, and the winds are calmer, allowing moisture in the air to transform into a thick layer of fog.
You weren't imagining it: This past weekend in San Francisco was especially chilly. And while it may not have been East Coast or Upper Midwest frigid, it was still bone-chilling for those of us acclimated to the temperate climate here. Yes, Sunday's temperatures set a new record for November 30 in San Francisco, with the high temp in the afternoon failing to crack to 50-degree mark for the first time since weather has been recorded in the city.