Though United Kingdom rainfall index fluctuated substantially in recent years, it tended to increase through 1969 - 1998 period ending at 1,082 mm in 1998.
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