YieldCast: Best Early-August Track Record In the Corn Industry Last 8 Years

The real test of the accuracy of U.S. corn and soybean yield forecasts takes place before the USDA issues their forecast in the August Crop Production report.  During critical periods leading into the report, yield forecasters do not have the benefit of “anchoring” to USDA estimates.  Futures prices often change substantially leading up to and through the report, so accurate yield forecasts have a very high value in early August.


The performance of YieldCast corn forecasts in early August has been truly outstanding.  Over the last eight growing seasons, the YieldCast forecast of U.S. corn yield in early-August averaged #1 closest to the final yield of 30 to 40 market analysts — measured before the release of the USDA August Crop Production report.  More so, YieldCast forecasts were among the three most accurate in 5 of the last 8 years (Figure 1, 2), including:


#1 most accurate of 32 forecasts in 2017
#3 most accurate of 31 forecasts in 2016
#1 most accurate of 40 forecasts in 2015
#2 most accurate of 34 forecasts in 2011
#1 most accurate of 29 forecasts in 2010


Additionally, since our inception in 2010, YieldCast forecasts averaged closer to the actual yield than forecasts in the USDA August Crop Production reports (Figure 3, 4).


Last year provides a great example of the value YieldCast normally has from April through early August (Figure 5).  The average market estimate of the U.S. corn yield leading into the August Crop Production report was 165.3 bpa (with a range of 162.4 to 168.0), while YieldCast was much higher at 169.7 bpa on August 8. The YieldCast forecast was higher because its objective modeling of crop and weather data indicated weather was not as poor as perceived. A couple days later on August 10, the USDA forecasted a yield of 169.5 bpa, showing the yield was likely higher than the market perception. YieldCast forecasts continued to increase into October, but fell short of the actual yield of 176.6 bpa.  The value of YieldCast generally diminishes after mid-September as the crop matures and more is known about actual yields.



YieldCast soybean forecasts have not been as accurate as for corn through early August, but averaged better than the market and very similar to the USDA over the last eight years, and were among the three most accurate of 30 to 40 market analyst forecasts twice in the last 3 years after we adjusted the YieldCast models to reflect changing technology (Figures 6, 7, 8).


YieldCast is a weekly service of T-storm Weather, and is released every Tuesday at 12 PM Central Time (1700 UTC) from April into October.  If you are not subscribed to YieldCast and would like information for a subscription, please contact us.


Note that data and figures discussed on this page are an update to the full research study that was performed last year.


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Figure 8