Bioclimatic variables calculated from statistically-downscaled historical (1901-2000) CRU TS 2.1 climate data and projected future (2001-2099) CMIP3 A2 and A1B simulated climate data on a 30-second grid of the northwest United States and southwest Canada,

This data set consists of a set of bioclimatic variables calculated from monthly mean temperature (degrees C), total precipitation (mm), and possible sunshine (%) data on a 30-second grid of the northwest United States and southwest Canada. Historical climate data for 1901-2000 were developed from the CRU CL 1.0, CRU CL 2.0, and CRU TS 2.1 data sets (http://www.cru.uea.ac.uk/cru/data/hrg/). Projected future climate data for 2001-2099 were developed using climate model simulations produced by five coupled atmosphere-ocean general circulation models: CCSM3, CGCM3.1(T47), GISS-ER, MIROC3.2(medres), and UKMO-HadCM3. These climate simulations were obtained from the World Climate Research Programme\'s (WCRP\'s) Coupled Model Intercomparison Project phase 3 (CMIP3) multi-model data set (http://www-pcmdi.llnl.gov/ipcc/about_ipcc.php). We used simulations produced under the Special Report on Emissions Scenarios (SRES) A2 and A1B greenhouse gases emissions scenarios. Additional documentation on the climate models is available at: http://www-pcmdi.llnl.gov/ipcc/model_documentation/ipcc_model_documenta…. Shafer et al. (2015, PLoS ONE) describe the methods used to create the downscaled climate data from which the bioclimatic variables are calculated. To calculate bioclimatic variables requiring a daily time-step, we created pseudo-daily climate data by bilinearly interpolating monthly climate values to individual days. Variables in this data set that are calculated from pseudo-daily data include chilling period, frost-free days, growing degree days (GDD0 and GDD5), and snowfall snow water equivalent. The bioclimate data in this data set were developed for use in modeling species and ecosystem responses to climate change and may not be suitable for other applications. Specifically, these data are numerical estimates of historical bioclimate and projections (not predictions) of potential future bioclimate. The data are provided in self-documenting netCDF files, which provide additional details about the data.