This dataset includes herbaria specimen records that report collection ___location and date (from 1895 – 2013) for grasses from the Southwest Environmental Information Network (http://swbiodiversity.org/seinet, Accessed 3 March 2014; 79% of records) and Global Biodiversity Information Facility (http://www.gbif.org, [accessed 3 March 2014]; 21% of records) for 12 states in the western United States. Associated climate data include monthly mean temperature, maximum temperature, minimum temperature, and precipitation from the herbaria record locations from climate rasters provided by the PRISM Climate Group (http://www.prism.oregonstate.edu, [accessed 1 May 2014]). We derived climate variables expected to be biologically meaningful for plant performance based on annual trends, seasonality, and extreme conditions (Bioclim, http://www.worldclim.org/bioclim, [accessed 14 May 2014]) using the PRISM monthly temperature and precipitation values.