Heavy rainfall across Iowa slowed the opening of the 2026 harvest during the Sept. 7-13 reporting period, according to USDA crop progress data. Farmers had harvested only 2% of the state's corn acreage, while soybean harvest had not yet begun. The situation matters economically because Iowa is a major U.S. corn and soybean producer, and prolonged wet conditions can reduce field access, compress harvest windows and increase pressure on machinery, labor and operating costs. Despite the difficult weather, crop condition ratings remained strong.

Corn development is broadly on schedule, but harvest is only beginning. USDA reported 38% of Iowa corn had reached maturity, matching the five-year average but trailing the 2025 crop by 7 percentage points. Nearly 90% had reached the dent stage, while 76% of corn was rated good to excellent. Soybeans were rated 74% good to excellent, but development was slower: 22% of the crop was dropping leaves, 10 points behind last year and 6 points behind the average. Normally, about 1% of Iowa soybeans have been harvested by this point.

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Iowa Rainfall Surges Far Above Normal as Farmers Prepare for Harvest

Weather is now the immediate challenge. State Climatologist Justin Glisan described conditions as "excessively wet," with some weather stations receiving 400% to 600% of normal rainfall. Iowa averaged 2.05 inches of precipitation during the week, compared with a normal 0.84 inch. Western and central Iowa received the heaviest totals, including 7.76 inches at Guthrie Center. With additional rain expected, Iowa Agriculture Secretary Mike Naig encouraged producers to use downtime to prepare equipment and complete other farm work before harvest activity accelerates.

Key Iowa Harvest Numbers