Abstract
The month of March 1843 has been characterized as exhibiting the greatest temperature anomaly of any month during the period of instrumentally measured meteorological data in the United States. The March 1843 departure patterns from recent temperature normals are compared to those of February 1936 which were of the same magnitude (−30°F/−16.7°C), though perhaps of lesser areal extent. The frigidity of the air during February 1936 set some all time low temperature records that still stand today.