The drought-inducing winds in the area under consideration are analyed according to observation data. Their injuries to winter wheat are brought out by eliminating the effect of soil moisture, and a formula is obtained for calculating drought-inducing wind index, K=(C/C₀)(T≥30)/(R≤30), where C is 13 hr. (or 14 hr.) wind velocity in m.sec.^-1;C₀ critical wind velocity(=3 m sec.^-1);T, 13 hr. (or 14 hr.) temperature in °C; R, relative humidity in %. The day is free of drought-inducing wind, if K<1. With K=1一2, it may be specified as a day with light drought-inducing wind;with K=2一5, a day with moderate drought-inducing wind; and with K>5, a day with intense drought-inducing wind.