This data release contains output from a numerical snow simulation for a 65 kilometer (km) × 81 km model domain in parts of Montana and Wyoming, United States, encompassing the Gallatin River watershed upstream of the U.S. Geological Survey streamgage near Gallatin Gateway, MT (06043500). Weather Research and Forecasting (WRF) Model convection-permitting and orography-resolving regional climate simulations with 4-km horizontal resolution provided the atmospheric forcing conditions to SnowModel in both a historical and future climate scenario. Two continuous, 13-water-year (2001-2013) WRF model simulations were utilized: (1) a historical climate control (CTL) simulation forced using ERA-Interim reanalysis, and (2) a future climate simulation using the pseudo-global-warming (PGW) method that uses the ERA-Interim reanalysis for the same period as (1) and adds an ensemble mean climate delta from the end of the century (2071-2100) for the most extreme 5th Coupled Model Intercomparison Project (CMIP5) Representative Concentration Pathway (RCP) 8.5 scenario. The ten SnowModel simulated outputs provided in this data release include (1) air temperature (tair), (2) precipitation (prec), (3) solid precipitation (spre), (4) liquid precipitation (rpre), (5) liquid water supplied to the soil-snow interface from snowmelt (smlt), (6) snow sublimination (ssub), (7) liquid water supplied to the soil-snow or soil-air interface either from snowmelt or rainfall (roff), (8) snow depth (snod), (9) snow water equivalent depth (swed), and (10) snow density (sden). The simulations used to produce these outputs were conducted on a 30-m geospatial grid. Land cover information for the simulation was provided by the 2010 North American Land Change Monitoring System and elevation information was provided by the U.S. Geological Survey National Elevation Dataset. The historical (CTL) and future climate (PGW) simulations were conducted using annual precipitation bias correction surfaces (prec_cf), which were computed by comparing SnowModel-simulated CTL snow water equivalent to Natural Resources Conservation Service snow telemetry station (SNOTEL) observations to generate a precipitation correction that was interpolated using SnowModel.