The temperature yesterday afternoon was squarely in the mid-teens, but the prospect of discomfort, goosebumps, and shrinkage couldn’t dissuade hundreds of people from getting on the subway at various locations around the city and promptly taking off their pants.

Yes, it was time once again for the annual Improv Everywhere No Pants Subway Ride, which has gone from a seven-person prank when it first started in 2002 to the city-wide event that it is today. The rides began in seven stations in Brooklyn, Queens, and Manhattan, with all the pranksters disembarking in Union Square for a massive panty party.

The freezing-ass weather did confine most of the USQ festivities to within the station itself, and more than a few regular subway-goers were visibly annoyed that sections of the underground complex were clogged up with naked-legged folks. But in general the pantless proceedings provoked giggles and photo-taking (or a studied disregard) from the fully clothed.

As has been the case in recent years, the NYPD provided escorts along each ride, and there were dozens of officers on hand (and, for the most part, enjoying themselves) at Union Square.