It was Mark Twain who was credited with saying, "The coldest winter I ever saw was the summer I spent in San Francisco." And if he did, he was absolutely correct. Summer and winter are two sides of the same coin in the "City by the Bay," with a bone-chilling August, a red-hot October, and a rainy February. It has rarely ever snowed in San Francisco. Instead, winter is met with cold, blustery rain on occasion. The only predictable thing about San Francisco's weather is its unpredictability. Even in an otherwise freezing summer, temperatures can still reach a sweltering 100 F. Dressing in layers is the best way to be prepared because while most days are mild, the temperature can change quite quickly.
The fall semester often begins with lots of sunny, clear days, in which it's best to prepare a wardrobe of shorts and open-toe shoes. Scantily clad students can be found throughout campus in the first few weeks of the school year, and then not until after the rainy winter season has passed. Fog frequently engulfs the city, but usually it passes within a few hours. If you wear light layers, you’ll always be prepared.