Mountain river basins provide the majority of western North America with snowmelt runoff water resources throughout the late spring–early summer snowmelt season. However, this snowmelt water resource is extremely vulnerable to any changes in air temperature and precipitation. Studies of larger mountain river basins have projected potentially warmer and drier climates in the future, but the resolution of these studies is often incompatible with smaller basins and subsequent water resources planning. The purpose of this study was to test the potential of increasing the resolution of future climate projections by combining a series of surface and upper-level atmospheric datasets using a statistical downscaling technique and to then project how the future climate could change for a typical small snowmelt fed mountain basin in western North America, the Animas River Basin, Colorado, over the course of the 21st century. Results indicated that, in general, a warmer and drier climate may occur, with this technique more effectively capturing changes in air temperature over precipitation. With this kind of data at hand, increasing levels of sustainable water resource planning for a range of future climate scenarios may be achieved for mountain river basins of a similar scale.