
Iowa State extension agronomist Mark Licht advises that planting decisions should depend on soil temperature and moisture rather than the calendar. He gives critical planting dates of May 18 for corn and May 20 for soybeans in Iowa, with yield losses expected after them.
Planting guidance affects expected acreage timing but does not signal a change in crop supply. Price impact is minimal at this stage.
After 445 past neutral weather events, Corn moved a median +0.1% over 5 sessions (52% higher; middle half -1.4% to +1.6%), and +0.7% over 20.
After 324 past neutral weather events, Soybeans moved a median +0.0% over 5 sessions (52% higher; middle half -1.4% to +1.7%), and +0.7% over 20.
Moves of each commodity's benchmark from the last close before the event. Historical reads pool past events of the same kind; they describe what happened, not what will. Not investment advice.