The ROC Area ( Relative Operational Characteristic Area ) is defined as the area which covered by the line of (0,0), (1,1) and (0,0), point(s) of hitting rate and false alarm to point of HR, FA, (1,1). Therefore, ROC Area is [ 0, 0.5 ], The ROC area will represent the overall economic benefits that users distributes equally with respect to the cost/loss ratio can attain from using different probabilistic forecast systems. ROC area of 0.5 corresponds to perfect forecasts while 0 indicates no skill above sample climatology.