Agriculture > Perennial Crop General Approach > Tart Cherry Development and Production > Growing degree days (GDDs)

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Growing degree days (GDDs)

Growing degree days are used to monitor heat accumulation and estimate the development and timing of important phenological stages. A “degree day” should not be thought of in the same way as a “calendar day.” A degree day is generally defined as the departure of the mean daily temperature from a given threshold. Thus, one degree day corresponds to one degree departure above (or below) the threshold on a given day.

As an example, if the mean temperature for a particular day is 71ºF and the threshold used for the degree day calculation is 41ºF, then there are 30 “degree days” for that particular calendar day. Degree days are then accumulated over the season and/or the entire year. The accumulated values can be quite large.

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