We recently moved to the Bay Area from Chicago. I would like to know why it’s so darn cold here in the summer and warmer in the fall.
—Mary-Lynn Wilson, Oakland, Calif.
San Francisco summers are characterized by cloudy, cool, damp and foggy weather with daytime temperatures generally in the 60s, making them the coolest of any major U.S. city. The coolest readings are found closest to the oceans with warmer temperatures inland. Most afternoons feel quite chilly as a strong sea breeze sets in driven by the large temperature difference between the chilly Pacific Ocean waters and the intense heat in California’s Central Valley. Some of the Bay Area’s warmest weather occurs in the spring and fall when high pressure builds in the Great Basin and Pacific Northwest and downslope offshore winds send temperatures soaring and humidities plunging.