An integral part of the assessment of storm loads on water quality is the statistical evaluation of rainfall records. Hourly rainfall records of many years duration are cumbersome and difficult to analyze. The purpose of this rainfall data analysis program is to provide the user with a tool for summarizing and statistically characterizing a rainfall record of interest using U.S. Weather Bureau magnetic tapes. Statistical analysis of variables of interest (volume, duration, intensity, and time between storms) are given to determine seasonal trends which are of importance in accessing impacts and selecting control alternatives for storm related loads.