<Tr> <Th> Areas affected </Th> <Td> Canada Central United States Eastern United States Northern Mexico </Td> </Tr> <Tr> <Td_colspan="2"> Part of the 2013--14 North American winter </Td> </Tr> <P> The 2014 North American cold wave was an extreme weather event that extended through the late winter months of the 2013--2014 winter season, and was also part of an unusually cold winter affecting parts of Canada and parts of the north - central and upper eastern United States . The event occurred in early 2014 and was caused by a southward shift of the North Polar Vortex . Record - low temperatures also extended well into March . </P> <P> On January 2, an Arctic cold front initially associated with a nor'easter tracked across Canada and the United States, resulting in heavy snowfall . Temperatures fell to unprecedented levels, and low temperature records were broken across the United States . Business, school, and road closures were common, as well as mass flight cancellations . Altogether, more than 200 million people were affected, in an area ranging from the Rocky Mountains to the Atlantic Ocean and extending south to include roughly 187 million residents of the Continental United States . </P>

When was the last time it was this cold in atlanta