Crosswind warning device

The crosswind warning device comprises a stand column, an air bellow and an air guide pipe, one end of the air guide pipe is closed, the other end of the air guide pipe is open, the air guide pipe is communicated with the interior of the air bellow, the two ends of the air bellow are each provided with an air inlet only capable of conducting in one direction, and a piston capable of transversely moving inwards and outwards along the inner wall of the air guide pipe is arranged in the air guide pipe; the top of the stand column is fixedly connected with an upper transverse rod and a lower transverse rod, a rotating cylinder is rotationally installed between the free ends of the upper transverse rod and the lower transverse rod, a plurality of warning marks used for representing different wind power grades are arranged on the outer wall of the rotating cylinder, and a rotating component driving the rotating cylinder to rotate is installed on the upper transverse rod. The outer side of the piston is connected wi