Provided we're not all underwater at this point, here are a few choice things to do in San Francisco on this very, very rainy day. (Reminder: Be sure to check weather warnings before heading out.)
Walk Grace Cathedral's indoor labyrinth
Few places in the city are as tranquil and poignant as Grace Cathedral. Stop in for a quick prayer (it's nondenominational, so all are welcome) and then walk around the indoor labyrinth while keeping "an open heart and an open mind." It's made for meditation. Don't forget to check out the Keith Haring altarpiece, too.
The Palace Hotel's Garden Court is a nifty place to have tea or lunch, especially during the rain under the stained glass dome. (You know, the one that Sean Penn fell through in The Game? That one.) Check it out in December for maximum holiday saturation via their massive Christmas tree and intricate gingerbread house.
Stay dry on public transit
As soon as a few droplets fall from the sky, your everyday fellow passenger turns into a confused, scared mongrel. (It's not our fault; like Gremlins, we should never get wet.) Be patient and courteous with each other. Also, you won't be able to find a dry seat. It's almost mandatory that at least a half cup of water must be poured onto every seat during a rainfall, bog or small. (Remember to put your umbrellas on the floor, you heathens!)
Buy a clear umbrella
Sure, you might look like a 12-year-old girl on her way to school, but your mood will be greatly improved with a clear umbrella. Hand to god, it'll forever change your views on umbrella hues. Being able to see what's going on around you will not only help you avoid bumping into passersby, but the skylight effect will cheer you up.
Go West
Hear me out. Should you find yourself in the Outer Richmond, head a few more blocks west to the historic Cliff House. The restaurant's floor-to-ceiling windows are perfect for witnessing the Pacific Ocean's wrath during tumultuous storms. [WARNING: Flash flood warnings, high surf and high wind advisories are in effect. Please proceed with caution. We do not recommend going to Ocean Bean during storms.]
The language of cinema is universal... and perfect for crummy weather
Movies were made for rainy days. Especially on the weekdays. Check out any number of films playing today.
House of Air
Bounce around on the 42 trampolines at House of Air. The indoor trampoline park, inside a former airplane hangar in the Presidio, is an excellent way to stay dry while toning your leg muscles.
Nap time
Or, just stay in and sleep for the rest of the day.