Have you ever heard the term “degree days?”  Heating and cooling degree days are derived from temperature data and used to monitor the amount of energy that is needed for heating and cooling.  So if you have a winter like this past one, with a much lower number of heating degree days than average, you are likely to pay less on your heating bills (although of course what fuel you are using and what the market price is are also important).

Growing degree days are used to monitor the development of plants and also of insect pests, which require a certain amount of heat or temperatures above a certain threshold to go through their life cycle.  (A simple explanation can be found here.) For plants, often a base temperature of 50 F is used.  Some plants like corn also have an upper threshold because they don’t do well in extreme heat (leading to modified growing degree days), while others do not.

Here are some resources on GDD for insect pest management and where to find the calculated values.  If you have others you use for the Southeast, email them to me and I will add them to the list.

University of Kentucky: Predicting insect development using degree days

University of New Hampshire: Using growing degree days for insect management

Michigan State University: GDD of landscape insects

Here are some places to find calculated GDD information using your selected temperature thresholds:

Midwestern Regional Climate Center cli-MATE: https://mrcc.isws.illinois.edu/CLIMATE/ has data for the entire US.  You must sign up for a free account.

Georgia Weather Network: https://www.georgiaweather.net has a calculator available under the “calculator” section.

AgroClimate: https://agroclimate.org/tools/Growing-Degree-Days/

Source: Valerie Everett, Commons Wikimedia