The GPM Ground Validation Environment Canada (EC) Radiometer GCPEx dataset contains retrievals of temperature, water vapor, relative humidity, liquid water profiles and surface parameters acquired by a passive microwave radiometer during the GPM Cold-season Precipitation Experiment (GCPEx) in Ontario, Canada, February 14, 2012 through March 1, 2012. GCPEx addressed shortcomings in the GPM snowfall retrieval algorithm by collecting microphysical properties, associated remote sensing observations, and coordinated model simulations of precipitating snow.