The application of the group post-appraising method in weather forecasting is presented.It happens that the result is of difference to the forecasting of a certain day from different technological sources when possible weather situation prediction is made,or that each predictor will draw a different conclusion based on forecasters'own technological devices or approaches.Only then is it necessary by the approach to piece together various results as a whole so that group decision can be reached.The application is to make an overall evaluation of each result about rainfall and rain region plus the result based on experience.It has proved that the application is unique in this field and more effective and has actually become one of the effective approaches.