Growing Degree Days

Between 1970 and 2021, growing degree days (GDD)—a measure of heat accumulation used to track plant and pest development—increased at 97% of 246 analyzed stations across the contiguous U.S. The average increase was 525 GDD, with the most significant rises occurring in the West, Southwest, and South. While some plants may benefit, increased GDD is linked to higher water and heat stress, altered agricultural schedules, and longer pollen seasons that exacerbate health issues like asthma and hay fever.

• From 1970 to 2021, growing degree days (GDD) increased at 97% of the 246 analyzed stations in the contiguous U.S., with an average increase of 525 GDD and an average annual rate of change of 10 additional GDD per year.
• The most substantial increases in GDD were concentrated in the West, Southwest, and South. The five highest increases were recorded in Reno, Nev. (+1818), Las Vegas, Nev. (+1816), Tucson, Ariz. (+1585), El Paso, Texas (+1585), and Phoenix, Ariz. (+1537).
• Increased GDD can lead to negative outcomes, including greater potential for water stress in plants due to increased evaporation, particularly in the West and Southwest, as well as heat stress and reduced crop productivity.
• There is a correlation between higher GDD and the extension or earlier onset of pollen seasons for birch, oaks, and grasses, which may worsen economic losses and health conditions such as asthma and hay fever for millions of Americans.

APA

Anderegg, W., Irmak, S., Lo, F., & Kukal, M. S. (2022). Growing Degree Days. Climate Central. https://www.climatecentral.org/climate-matters/growing-degree-days

Chicago

Anderegg, William, Suat Irmak, Fiona Lo, and Meetpal S. Kukal. Growing Degree Days. Climate Central, 2022. https://www.climatecentral.org/climate-matters/growing-degree-days.

Wikipedia

{{cite report |last1=Anderegg |first1=William |last2=Irmak |first2=Suat |last3=Lo |first3=Fiona |last4=Kukal |first4=Meetpal S. |title=Growing Degree Days |publisher=Climate Central |date=9 March 2022 |url=https://www.climatecentral.org/climate-matters/growing-degree-days |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{anderegg2022growing, author = {Anderegg, William and Irmak, Suat and Lo, Fiona and Kukal, Meetpal S.}, title = {{Growing Degree Days}}, institution = {Climate Central}, year = {2022}, month = mar, url = {https://www.climatecentral.org/climate-matters/growing-degree-days}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }