Based on the mathematical statistics analysis on temperature changes and precipitation data in Suzhou City of Anhui Province in winter from 1955 to 2010, the study has shown that winter wheat in Suzhou always grows slowly in winter, especially under the double influences of drought and warmer winter, when irrigation is needed. According to the above results, by using Delphi technique, the three meteorological factors (precipitation, daily minimum temperature, and wind speed) are chosen, which have effects on winter irrigation, and their quantitative grades and weight coefficients affecting irrigation suitability are set up. And then, the meteorological suitability index for winter wheat irrigation in winter drought period is proposed and its computational model is built. Finally, combined with the appropriate technology of weather forecast, the study presented the weather forecast products for winter wheat irrigation in winter drought period. The case validation shows that the model has the ability to satisfy the needs of issuing the weather forecast products for farming.