Crop & Pest Report


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Weather Forecast (08/06/20)

The August 6 to August 12, 2020 Weather Summary and Outlook

Almost all of the North Dakota Agricultural Weather Network (NDAWN) recorded temperatures below average in the past week (Figure 1).  Temperatures are expected to be noticeably warmer this forecasting period with temperatures overall being near average with a mix of both warmer and cooler than average days expected.


There were two main periods of precipitation in the past week.  One on July 31 and the other on August 4 that lingered into August 5.  The rain totals for August 5, which included some 1-inch totals in Kidder County, because of deadlines, is not included in Figure 2.  Much of the rain expected in the next week looks to be occurring on Friday into Friday Night (August 7) although, there will be some hit and miss activity on other days.


Because of the very cold first half of May, the 2020 growing season didn’t start in many areas until the middle of May.  Using May 15 as a reference, Figure 3 shows the percent of average rainfall for NDAWN stations in the region.  I will emphasize that the background contouring does not necessarily reflect conditions in a given area, but does help visualize the areas that have been wet or dry so far this season.  With the exception of just a few spots near the North Dakota/Montana border the areas served by the NDAWN mesonet have generally been warmer than average since that cold snap in early May. 


The estimated hours with high relative humidity for the period of August 6 through August 12 can be found in Figure 4.  Most of the region will record fewer high humidity hours this week than what has been recorded in recent weeks.  The main exception looks to be southeastern North Dakota into west central Minnesota. 


The projected growing degree days (GDDs) base 50°, 44° and 32° for the period of August 6 through August 12, 2020 can be found in Figure 5.  With a warmer temperature week expected, more GDDs are forecasted this period than what occurred in the past week. 


Using May 1 as a planting date, accumulated growing degree days for wheat (base temperature 32°) is given in Figure 6.   You can calculate wheat growing degree days based on your exact planting date(s) here:


Using May 20 as a planting date, accumulated growing degree days for corn (base temperature 50°) is given in Figure 7.   You can calculate corn growing degree days based on your exact planting date(s) here:


Soybeans also use base 50° like corn, but NDAWN has a special tool for soybeans that is based on your planting date and cultivar and can estimate maturity dates based on average temperatures, as well as give you GDDs based on your planting date(s).  That tool can be found here:


Daryl Ritchison


Director of the North Dakota Agricultural Weather Network



This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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