Periods of anomalously cold temperatures impact regions of the globe every winter. Depending on the magnitude and duration of the occurrence, extremely cold periods may be deemed cold air outbreaks (CAOs), which can be detrimental to the agricultural industry and human health. A systematic CAO classification was developed from gridded NCEP/NCAR reanalysis data, from 1948 through 2017, based on a set of criteria concerning magnitude, duration, and spatial extent. Statistical analyses of the data were used to determine the overall trends in CAOs for different regions across the globe. This research will be used to further understand the large scale atmospheric mechanisms that precede these CAOs and how the specific mechanisms impact the location of CAOs.