Chicago Board of Trade grain and soy markets stayed all about the weather this week. When forecasters called for dry weather in the eastern U.S. Midwest, corn and soybean prices rallied. But by week’s end, parts of the eastern Corn Belt — notably Illinois, the top U.S. soy producing state and the No. 2 corn state, was benefiting from good rains.
Summer is always the most volatile time of the year for Chicago grain prices. But this summer is exceptionally volatile, which reflects large number of long positions held by big speculators and growing volume spread across two trading platforms: electronic screens and arm-waving pits.
There were many times, even a few years ago, when it was common for corn to spend an entire trading session in 1-cent range. On Tuesday, corn fell the 20-cent limit. The next day wheat jumped the 30-cent limit. Veteran floor traders, astute at making markets, struggled to keep heads above water.
Wheat prices also reacted to the weather. With global wheat supply projected at a 30-year low, more jitters about the U.S. winter harvest continued to jostle the market. The U.S. is not the largest wheat producer but is the largest exporter.
Mature winter wheat in the southern Plains was damaged by rains as harvesters tried to get the crop off the field. But weather late in the week was turning drier which should help improve harvest efforts in Texas, Oklahoma and Kansas.
Dry Midwest crop conditions were seen also stabilizing late this week, with corn and soybeans benefiting from scattered rains. The government will release updated condition ratings for the week next Monday. But all eyes will be on the USDA’s updated acreage report that will be released next Friday, June 29.
Talks was circulating this week on the trading floor that corn acreage will definitely be revised up. Ditto for soybeans, as a lot of drought-damaged soft red winter wheat grown in “double-crop” areas of the Ohio River and Delta states may have been plowed up and sown to more soybeans than usual.

Photo of Art Bunting in his corn field in Dwight, Illinois about 100 miles south of Chicago. Thte photo was taken by Mark Weinraub this week.