The pilot stated that he did not obtain any preflight weather briefing for the local flight. At the time of departure the wind was from 270 degrees at 9 knots, and after being airborne for about 1 hour 15 minutes, the wind picked up to 270 degrees at 17 knots with gusts to 28 knots. At that time he elected to return to the departure airport, and selected to land on the grass runway designated 28. He executed a normal traffic pattern, and on final approach with 20 degrees of flaps extended maintained 70 miles-per-hour. About the point he was “rounding out” a wind gust occurred raising the left wing. He immediately applied left aileron and right rudder inputs, and leveled the wings, but at that time the airplane had drifted to the left. The left main landing gear went into a ditch and the left wingtip was substantially damaged when it contacted corn crop adjacent to the runway. He further stated there was no preimpact mechanical failure or malfunction of the airplane or systems.