Area-averaged Growing Degree Days in Maryland in 2024

This analysis obtains Growing Degree Days and Modified Growing Degree Days for the calendar year from area-averaged daily maximum and minimum air temperatures. These parameters are used to estimate the growth and development of plants and insects during the growing season under the idea that development will only occur if the temperatures exceed some minimum threshold so enough warmth is accumulated. Because the actual development will differ for different plants and insects, and the presence of weeds and precipitation can influence the development, a base temperature of 50°F is generally considered acceptable for all plants and insects. However, this base temperature is best suited for the development of specific crops like corn, sweet corn, soybeans, tomatoes, and a few others.

The Growing Degree Days (GDD) are obtained when a base temperature of 50°F is established for the daily minimum temperature before calculating the daily mean temperature. The Modified Growing Degree Days (MGDD) are obtained when a base temperature of 86°F is set for the daily maximum temperature, and the base temperature of 50°F is set for the daily minimum temperature before calculating the daily mean temperature; these are specific to corn development as no appreciable growth is detected with temperatures lower than 50°F or greater than 86°F. Summary tables can be seen in the following links for Growing Degree Days at several base temperatures in the calendar year.

NOTE: The plots are created from NCEI's nClimDiv-Daily data set, v1.0.0. Data labeled as scaled on September 9, 2024.