Climatological analyses of manually digitized radar (MDR) data are presented to illustrate geographic, seasonal, and diurnal heterogeneities of precipitation over the United States east of the Rocky Mountains. MDR data consist of hourly radar reflectivity data for the contiguous United States at a grid scale of approximately 40 km. Analyses of MDR data for the period 1978--1992 are presented. MDR data are especially useful for studying the geographic contrasts in precipitation over the continental domain and the contrasts between land and ocean along the Gulf of Mexico and the Atlantic Ocean. Climatological analyses of fractional coverage of rainfall on a continental scale are developed using MDR data. High-resolution radar data from the RADAP II network are used to illustrate fractional coverage of rainfall within an individual MDR grid box. Intercomparison studies with rain gage data point to the potential for quantitative rainfall analyses based on MDR data. Analyses of MDR data illustrate the potential, and some of the difficulties, in using radar data for hydroclimatological studies. ¿ American Geophysical Union 1995