Corn and cotton are two of the main agricultural crops grown in Alabama. The purpose of this study is to determine the relationship between precipitation amounts and county and state-wide yields for these two crops. Results of statistical relationships using data since the 1940s agree with plant physiology and show that increased precipitation has the greatest effect on corn production during the month when the plant is silking and tasseling. This occurs during the month of May, June or July, varying from south to north across the state. Cotton production is most influenced by precipitation during the bloom stage, which occurs most often in July, but also varies with region within the state. Increased precipitation has a greater effect on both crops during drier than normal intervals than during periods with above average rainfall.