Growing Degree Days

What are Growing Degree Days?

Growing degree days (GDDs or GDD) as applied to the control of insect/arachnid pests of landscape plants, are a measure of accumulated heat calculated by subtracting 50 degrees from the average daily temperature(though for other objectives, GDDs may also be calculated by plant scientists and other plant specialists using a base other than 50 degrees). In New York State, base 50 GDD calculations are made from March to the end of September. Knowing the amount of accumulated base 50 GDDs helps plant professionals and home gardeners monitor stages of insect/arachnid pest activity or target control to a stage when the pest is most vulnerable.

Current information on base 50 growing degree day accumulation is available from the Northeast Regional Climate Center (NRCC). For the latest information from the NRCC concerning Westchester base 50 GDD accumulation since March 15^th,click the following link:http://www.nrcc.cornell.edu/industry/grass/grassWeb_dd.html

You may also wish to check out all the other useful information on the Northeast Regional Climate Center home page at: http://www.nrcc.cornell.edu/

Please contact CCE of Westchester, 3 West Main Street, Suite 112, Elmsford, NY 10523, if you have additional growing degree day questions at westchester@cornell.edu

NOTE: The above base 50 GDD accumulation from the NRCC is calculated from temperature readings taken at the Westchester County Airport. Base 50 GDD accumulation may be higher or lower than in warmer or cooler locations in Westchester County.

Please contact CCE of Westchester, 3 West Main Street, Suite 112, Elmsford, NY 10523, if you have any special needs.

For more information please e-mail westchester@cornell.edu.

Last updated August 14, 2020