The Unseen Sea: San Francisco's Famous Fog
"The coldest winter I ever saw was the summer I spent in San Francisco."
This quote, often attributed to Mark Twain, never made much sense to me until I actually experienced sundown in San Francisco. As any Bay Area resident knows, it can be 90 degrees during the day, but the minute the sun drops, the temperature plummets and the fog rolls in. Every evening, as if on cue, that heavy, wet blanket moves in to tuck the city to sleep.
The Unseen Sea: A Different Side Of San Francisco's Famous Fog. NPR.