December Starts Cold II

Yesterday in this space, I mentioned that no record lows have been set in the month of December since 1983.  There are two principal reasons for this.  The first is thermometer changes.  Many of the records in our cold season were set in the 1880s before what is now the National Weather Service set up standards for how all temperatures should be recorded back in 1891.

For example, the low temperature has not hit -40 degrees or lower since 1891 in Fargo Moorhead.  Another more significant reason why low temperatures records are more difficult to set is land use changes.  As Fargo Moorhead continues to grow, our heat island, the increase in air temperature caused by man-made objects replacing the natural landscape has become more significant.

Plus, the coldest temperatures are on clear, calm nights and with the official sensor very near the airport runway, dead calm air is difficult to achieve with the increase of flights at Hector Int’l keeping the air mixed up near the official sensor.