The pilot reported that he attempted to land on the first third of the runway, at an airspeed of 90 knots, while maintaining the runway centerline. During the landing flare, a wind gust turned the airplane approximately 10 degrees to the left. The airplane landed, went off the runway and into the grass, and struck runway lights and signs. Winds were reported as 30 degrees from the right, at 13, gusting to 17 knots