The GPM Ground Validation Composite Satellite Overpasses GCPEx dataset provides satellite overpasses from the Special Sensor Microwave Imager/Sounder (SSMIS) satellites (F-16, 17, 18) during the GPM Cold-season Precipitation Experiment (GCPEx) which took place in Ontario, Canada, January 17, 2012 through February 29, 2012. The radiometric data was matched up with other datasets necessary to carry out land surface emissivity studies. These other datasets include the NEXRAD National Mosaic and Multi-Sensor QPE (NMQ) radar mosaic for knowledge of rain structure and intensity at the time of the overpass, as well as the previous accumulated precipitation prior to the satellite overpass time, the NOAA Interactive Multisensor Snow and Ice Mapping System (IMS) snow mapping system (to identify surface snow or ice cover), and the NASA/GMAO Modern-Era Retrospective Analysis for Research (MERRA) land and atmospheric reanalysis (for background land and atmospheric state needed for microwave radiative transfer calculations). The identified SSMIS satellite overpasses passed within 700-km of the central field site.