In addition to the information provided in the Catchment-to-Canopy-Area Spreadsheet for large cities within the Desert Landscape Conservation Cooperative, the following websites give precipitation information by state:
Arizona: http://cals.arizona.edu/azmet
California: http://www.ggweather.com/climate/index2.htm
Nevada: http://www.wrcc.dri.edu/summary/Climsmnv.html (Scroll down for Nevada cities)
New Mexico: http://www.wcc.nrcs.usda.gov/snow/index.html