US Growing Degree Days Plummet

“Temperatures are much colder this year than the previous.” Excerpts from Ice Age Farmer | Sep 3, 2019

Most coverage of the difficulties plaguing the 2019 US season has revolved around the consequences of our “wettest year ever.” Rightly so, as the flooding across the nation continues to effect a substantial (and often fatal) blow to farmers’ operations. The flooding has been widely covered in most media, to the exclusion of another important factor: temperatures are much colder this year than the previous.

Cold temperatures pose problems for an already late crop to reach maturation. As Pro Farmer’s DTN Senior Ag Meteorologist mentions:

The extent of delayed planting of the 2019 U.S. corn crop appears to be coalescing around the idea that, in general, the U.S. corn crop is around three weeks late. With that in mind, the temperature trend takes on extra urgency for the crop.

Growing Degree Days are a measure of heat accumulation used to predict crop maturity. In the absence of extreme conditions such as unseasonal drought or disease, plants grow in a cumulative stepwise manner which is strongly influenced by the ambient temperature. In other words, GDD values provide a best case outlook as to plants’ pace to maturity.

If your GDD drops below certain thresholds, certain crops can no longer be grown.

Down 12.8!

95% of US ZIP codes experienced a colder growing season in 2019 than 2018.
On average, a US ZIP code received 87.2% of the heat accumulation as in 2019 — a 12.8% drop!