Development Stage and Spikelet Sterility Models were used to develop a monitoring and forecasting system of rice development and spikelet sterility in the Tohoku district, Japan in 1993. Actual crop data were provided by the Ministry of Agriculture, Forestry and Fisheries (MAFF). Daily Meteorological data (real-time and at 1 km × 1 km grid-mesh) and land-use information of the monitored area were provided through the Automated Meteorological Data Acquisition System (AMeDAS) and the Geographic Information System (GIS), respectively. The mesh-weather data and crop data inputted into the 2 models led to the monitoring and forecasting of rice development stages across the Tohoku district under climatic normals and actual weather conditions. Based on the information on the rice varieties planted in the monitored area, spatial distribution of mean air temperatures, their deviation from climatic normals, and spikelet sterility due to cool temperature were determined. The initial results show the importance of the 2 models as tools for monitoring and forecasting the rice development stages and spikelet sterility on a wide scale.