Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.
The average accumulated growing degree days in Atlanta are rapidly increasing during September, increasing by 641°F, from 3,877°F to 4,518°F, over the course of the month.