It is pointed out that two principal motivations exist for formulating and expressing weather forecasts in probabilistic terms,that is,the human's deepening cognition of the stochastic nature inherent in weather and climate change,and the increasing need for quantitative and precise decision-making in socioeconomic activities. The relation between probabilistic forecasting and meteorological economic decision-making is briefly discussed. Finally,a decision-making model is given to demonstrate that the economic value of probabilistic forecasts generally exceeds that of categorical forecasts.