On April 19, 2004, at 1413 Pacific daylight time, an Aeronca Champ 7AC, N83587, ground looped and collided with a runway sign during the landing rollout at the Hayward Municipal Airport, Hayward, California. The pilot was operating the airplane under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, was not injured; the airplane sustained substantial damage. Visual meteorological conditions prevailed, and no flight plan had been filed. The local personal flight originated from Hayward at 1409. In a written statement, the pilot reported that he was attempting to perform practice takeoff and landings. He stated that prior to takeoff, he received the local weather information from the airport's automated terminal information service (ATIS), which indicated that the wind was from 150 degrees at 12 knots. While abeam the runway identification numbers, in a left traffic pattern for runway 10L, he was cleared for the option by Hayward Tower. He opted to make a touch-and-go, and continued to short final. Despite the right crosswind, he touched down on the runway centerline without incident. During the landing rollout, with the airplane configured in a wheel-landing attitude, the pilot encountered a strong gust of wind. The right wing lifted, and the tail was displaced to the left of centerline, resulting in a weathervane to the right. The pilot inputted full opposite rudder and aileron in an effort to counteract the wind conditions. The airplane veered to the right, and continued off the runway. The airplane's tail collided with a taxiway identification sign, and the airplane continued into a ditch that was located between the two runways. The pilot attempted to regain control of the airplane, to no avail; the left main landing gear collapsed and the propeller impacted the ground. The pilot reported no preimpact mechanical malfunctions or failures with the airplane. The ATIS information "LIMA" was valid during the approach. It reported that the wind was from 150 degrees at 12 knots; however, ground control never verified that the pilot had received the current information. The control tower did not take a weather observation immediately after the accident occurred.