In the process of analysis of agricultural and weather factors influence on winter wheat yields it was revealed that the critical factors for the yield formation are (totally in Ukraine): the quantity of days with temperatures below 17 degrees of frost Celcius; the quantity and intensity of precipitation; quantity of days with temperatures exceeded 0 and 5 degrees of heat Celsius in winter time period. All above listed weather changes effect historical yields and make them differ very much year to year. Thus, using above listed factors winter wheat yield equalizations and coefficients that may be used for yield forecast were calculated. The consistency of the equalization’s results for winter wheat production was discovered for total Ukraine winter wheat production number. But these equalization’s coefficients need to be corrected with simple regression equalization every year. Correlation coefficients between the real yield and estimated yield under the calculated equalizations is 0.71 and 0.64, when p < 0.01. As yield is the main factor of winter wheat production in Ukraine, so this method could be used for estimation of wheat production and used for official wheat crop prognosis to lead the agricultural policy in Ukraine.