A procedure is developed which provides preharvest forecasts of the probability distribution of U.S. harvest time average corn prices. Crop-weather models are used to estimate the relationship between corn yields, technology trends and weather conditions for seventeen corn producing regions in the U.S. Corn Belt at monthly intervals throughout the growing season. Probability distributions of U.S. corn production forecasts are derived based on historic production forecast accuracy. To produce price forecasts, a corn price model is estimated from corn supply and demand information available to the market at harvest time. Forecasts of the probability distribution of U.S. harvest time average corn prices are calculated from corn production forecast distributions and current USDA projections of beginning stocks, feed use, exports, and old crop total corn usage.