It's a chilly Sunday for an annual event called "No Pants! Subway Ride 2013," but organizers say they still expect to have a turnout similar to last year, when more than 600 people rode BART and San Francisco Municipal Railway without pants.
Participants are required to meet 4 criteria: be willing to take their pants off before boarding public transit, keep a straight face while pant less, bring at least $10 for a BART or MUNI ticket, and leave a few items of clothing on for the sake of legality and public decency.
Riders are scheduled to come in two waves and all will end the event by convening in front of City Hall in San Francisco for a group photo.
The first wave of pant less riders plan to come from all stops on BART and MUNI and convene at the San Francisco Montgomery Station at 1:15 p.m.
Those riders will then walk down Market Street to meet the second wave of riders at the Civic Center Station at 1:35 p.m.
According to the event's facebook page there may be even more riders than last year: more than 1,065 people have said they will participate, and another 677 said they might.
The event is described as "improvisational" and designed to surprise people unaware of the day's plan.
Pants-free people are encouraged to walk into stores, bars, bathrooms and malls, acting as if it were normal to go pant less on a frigid January afternoon.
Bay City News Service contributed to this post.