The station record low for Fargo-Moorhead occurred on this date in 1887. The record shows a low temperature of 48 below. This temperature was part of a long cold snap in a terribly cold winter and was part of a four-day string of extremely cold temperatures from Jan. 6-9 of 43 below, 39 below, 48 below and 38 below zero. Daily high temperatures were 20 below zero for three of those days.
Other temperatures into the minus 40s were recorded at other times in the 1880s but not since 1888. This happened a long time ago, and there are questions about the records. Most importantly, the use of thermometer shelters with roofs to negate radiational cooling was not standard before 1890.
On the other hand, the world was colder then and a shelter would not have affected the daytime temperatures which were extremely cold.
Also of interest is the fact that temperatures from the first five days of 1887 are missing from the record. Who knows, maybe it got to minus 50?