"The coldest winter I ever spent was a summer in San Francisco."
Alright, so Mark Twain may never have actually said it himself. But the statement still stands.
As any naïve tourist shivering miserably in a tank top and Bermuda shorts might attest, summertime in San Francisco can be downright frigid.
Welcome to the infamous "June Gloom."
Even on days when the temperature in nearby cities climbs into the luscious 90's (°F), it's not uncommon to find much of San Francisco shrouded in a thick blanket of bone-chilling fog.
If you're still a bit foggy (sorry, couldn't resist) about why that is, scroll through this great interactive explainer created by Newsbound.
For a bit more clarity (about the fog, that is), watch the beautiful time-lapse film (at top) by Simon Christen, and below, this short video by KQED's Quest that digs deeper into the science of coastal fog.