This metadata record describes monthly input and output data covering the period 1900-2015 for a water-balance model described in McCabe and Wolock (2011). The input datasets are precipitation and air temperature from the PRISM group at Oregon State University. The model outputs include estimated potential evapotranspiration (PET), actual evapotranspiration (AET), runoff (RUN) (streamflow per unit area), soil moisture storage (STO), and snowfall (SNO). The datasets are arranged in tables of monthly total or average values measured in millimeters or degrees C and then multiplied by 100. The data are indexed by the identifier PRISMID, which refers to an ASCII raster of cells in an associated file named PRISMID.asc. Water-balance model inputs and outputs also can be linked to a file (PRISMID_LL.csv) of latitude and longitude values in a separate comma separated data file based on PRISMID values. Each input and output variable comma separated file contains 10 years of monthly data for all 481639 PRISMID raster cells in the conterminous United States. The files containing input and output data can be georeferenced by joining them to an ASCII raster of PRISMID cells, named prismid.asc. The source for the input data is the PRISM (Parameter-elevation Relationships on Independent Slopes Model) Group at Oregon State University (http://www.prism.oregonstate.edu/historical/ and http://www.prism.oregonstate.edu/recent/). These data were downloaded from the PRISM web site on various dates.