Growing degree days
Updated June 15, 2022
Definition and history: Degree-days (DD) or Growing Degree Days (GDD) are units of total accumulated heat that are used to forecast everything from plant growth to pest infestations. The value of using temperature to predict plant and animal growth was recognized by the French scientist Renè A. F. de Rèaumur in 1735. By adding together the daily average air temperatures that occurred during the life cycle of several different plant species, he discovered that the sum of temperatures for each…