Thirteen years of precipitation d²H, d¹⁸O, and ³H data for three western United States continental interior weather stations, supplemented with 60 years of precipitation data, have been analyzed. The stations are located 1,000 to 2,000 km from four ocean moisture sources. Precipitation was evaluated relative to storm track trajectory, the El Niño-Southern Oscillation Oceanic Niño Index (INO), orography, precipitation amount, air temperature, month, and season. The INO was not fond to correlate with precipitation flux or isotopic composition. Tritium deposition was evaluated relative to the ‘spring leak’, thunderstorms, surface evaporation, storm tracks, and seasons. Local meteoric water lines and the Global Meteoric Water Line were compared. Winter precipitation is isotopically depleted and summer precipitation is isotopically enriched. Factors affecting the stable isotopes include winter cold cloud temperature, summer rain droplet partial evaporation, gradual rain out, and multiple episodes of soil moisture re-evaporation and subsequent re-precipitation.