United States of America - National rainfall index

An indicator, developed by FAO, which represents the quality of the crop growing season. The NRI yearly results take into consideration the precipitation that year, the average precipitation over the period 1986-2000, the seasonality of the main crop-growing season (distinguishing between northern and southern hemispheres), and what areas of the country are wetter. The median of each five year period is provided. Note: due to methodological differences, this variable is not comparable to average precipitation