Preliminary August weather summary plus the September outlook for corn, soybeans, and sorghum

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The preliminary data shows that August tied for the 7th coolest on record. The statewide average temperature was 72.7 oF, which was matched in August of 2004. All divisions were cooler than normal with departures ranging from -3.6 oF in the Northwest to -5.0 oF in the Southeast.

The cooler-than-normal temperatures were coupled with near-normal rainfall. The statewide average precipitation was 3.45 inches, which falls on the wetter side of the middle range of the distribution. Unfortunately, the rainfall was spread unevenly, with much higher-than-normal precipitation in the East Central and Southeastern divisions.

The updated outlook from the National Oceanic and Atmospheric Administration for September calls for an increased chance of drier-than-normal conditions statewide. The temperature outlook is split, with cooler-than-normal temperatures in the east and warmer-than-normal temperatures in the west. The central part of the state has equal chances of warmer- or cooler-than-normal conditions.

Corn is reaching the late stages of the reproductive period, with only 15% mature at the state level, but overall temperatures will slow down the rate of drydown and result in a longer period before the corn reaches harvest. For soybeans, the main factor in the coming weeks will be the lack of rain – potentially compromising seed filling and final yields. Lastly, for sorghum, development in August was slower than normal due to the below-average number of sorghum growing degree days (see below figure). This can potentially lower the probability of maturing before the first freeze.

Further details and information will be presented in future Agronomy eUpdate articles. Stay tuned!

Figure 1. Departure from normal sorghum GDDS (based on data from


Mary Knapp, Weather Data Library‚Ä®

Ignacio Ciampitti, Crop Production and Cropping Systems Specialist‚Ä®