The Very Wet and Very Dry Summer of 2023 in the United States (and Its Consequences for the U.S. Corn Crop)

The 2023 meteorological summer (June-August) in the United States was both very dry and very wet, with extreme precipitation variation. As the map posted below shows, this was the driest summer since (at least) 1895 over several widely scattered parts of the country, including western Oregon, southern Arizona, western New Mexico, southern Louisiana, southeastern Texas, and the southeastern corner of Minnesota. The map also shows a small area near California’s Bay Area as having experienced its driest summer since 1895, but this particular depiction is misleading. Like most of the rest of the state, this region experiences negligible summer precipitation, getting a little over a tenth of an inch on average (see the table posted below for Antioch, CA). The difference between 0.01 inches and 0.15 inches may be large in percentage terms, but it means next to nothing in regard to actual conditions.

The 2023 summer drought in southern Minnesota, Iowa, and adjacent areas is concerning, as this area forms the heart of the U.S. corn belt. The official Drought Monitor Map shows severe to extreme drought over much of the same area. Curiously, this map also shows extreme long-term drought in parts of Kansas and Nebraska that experienced well above average summer precipitation this year. Some critics complain that the U.S. Drought Monitor is too slow to revise its mapping as conditions change.

Given such dry conditions over much of the corn belt, one might expect a reduced U.S. corn harvest in 2023. But according to an August 8 Reuters headline, “U.S. Farmers Expect Corn Harvest Could Be Second-Biggest Ever,” with the article explaining that “rains during July shepherded the crop through its critical development phase, offsetting dry conditions early in the season and hot summer temperatures.” A Successful Farming article outlines the problems faced by Minnesota farmers due to a three-year drought, while noting that technical improvements have mitigated the damage:

Bob Worth, president of the Minnesota Soybean Growers Association and a corn and soybean farmer in Lincoln County, Minnesota, said that improvements in seed technology is saving his farm from complete disaster despite the dry conditions: “If we had the same hybrids that we had in my early farming years,” Worth said, “we wouldn’t have a crop with as little rain as we’ve gotten.”

Despite its relatively healthy 2023 corn crop, the United States just lost its position as the world’s top corn exporter. The title was handed over to Brazil, as was that for soybeans a few years ago. According to a recent Bloomberg report (cited in Farm Policy News):

For more than half a century, US farmers dominated the international market for corn, shipping more of the critical crop than any other country to feed the world’s livestock, fill its stockpiles and manufacture its processed foods. No more. In the agricultural year ending Aug. 31, the US handed the corn-exporting crown to Brazil. And it might never get it back.

Other parts of the United States saw record-breaking precipitation in the summer of 2023. As the first map in this post shows, much of northern New England, eastern Michigan, southern California, central Wyoming, eastern Colorado, and south-central Montana experienced their wettest summer since 1985. Tropical Storm Hilary was responsible for most of this precipitation in southern California, and for some of it in central Wyoming and south-central Montana.

If the summer 2023 precipitation map had included the first three days of September, its depiction of the southwestern quadrant of the United States would have been quite different, showing much higher figures for eastern Arizona, Nevada, and parts of northern California (see the map below). A rare early-September cut-off low-pressure system rotated off the cost of far northern California during this period, bring unprecedented precipitation to many areas, as well as widely mocked misery to campers at the Burning Man Festival in northwestern Nevada.

Note on this map the extraordinarily steep gradient on the seven-day late-August to early-September rainfall map in northern California. Here areas getting less than five percent of average precipitation in this period are almost adjacent to those getting over 600 percent. This seeming anomaly was partly the result of a sharp precipitation cut-off in the recent storm, with entrained bands of rainfall hitting some areas repeatedly while leaving nearby areas completely dry. But it is also, again, a consequence of the extremely dry average conditions in this region at this time of the year.

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