The flight instructor reported that, following simulated instrument flight instruction to a private pilot-rated student, he took the controls while on approach to the airport. He added that it had started to rain but that the runway was still visible. Before touchdown, the instructor kept the airplane in ground effect to reduce the airspeed, and the airplane touched down about halfway down the 3,578-ft-long runway, bounced twice, and touched down again. He then applied brakes, and the student "got the flaps up." After exiting the runway onto a taxiway, the instructor applied brakes, but the "airplane was still traveling too fast when [it] entered the ramp," and it veered slightly left of the taxiway centerline and struck three unoccupied airplanes on the ramp. The airplane sustained substantial damage to the left wing and left-wing spar box. The instructor reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The airport's automated weather observation station reported that, about the time of the accident, the wind was from 200° at 16 knots, gusting to 23 knots; visibility was 1 statute mile; broken clouds at 3,900 ft; temperature 81°F; dew point 73°F; and heavy rain. The instructor landed the airplane on runway 27C.