Barring a blizzard or other unforeseen weather emergencies, the 12th annual Jordan’s Polar Plunge will be held Saturday at Plymouth Beach. Registration is scheduled to start at 11:30 a.m., and the plunge will take place a bit later than usual — at 1 p.m. — because of high tide. Last year the fund-raiser drew over 600 “plungers” and more than 1,000 spectators, according to event spokeswoman Catherine McKenna. “We’re hoping for the same numbers,” she said. “It’s a really fun day.” Many participants show up in costumes, appearing as Smurfs, G.I. Joe, and other characters from TV shows and movies. The proceeds benefit the Jordan Hospital Club Cancer Center at Beth Israel Deaconess-Plymouth. For more information or to register online, visit www.jordanspolarplunge.com.