As of September 25, 2026, the AIFS ENS indicates average daytime highs near 68°F and overnight lows around 57°F over the next five days across the core Corn Belt. Looking ahead, the AIFS ensemble precipitation looks widespread light to moderate, averaging roughly 0.82 inches in days 1–5 (heaviest in central Iowa (including the Des Moines area) (1.7 inches) and lightest in northeastern Iowa, northern Illinois and southern Wisconsin (0.2 inches)), 1.26 inches in days 6–10, and 0.19 inches in days 11–15. Harvest is underway or rapidly accelerating across the Corn Belt. Corn is largely at or past black layer (R6) and soybeans are at full maturity (R8). Field activities center on combining as grain reaches workable moisture. Prolonged wetness in parts of the western belt has also raised concerns about stalk integrity where mold or fungal growth has weakened hybrids. Weather now primarily affects harvest progress, grain moisture, field trafficability, and lodging risk in weakened standing corn. Through September 22, the wettest of the four Corn Belt quadrants on a 15-day basis was northeastern Iowa, northern Illinois and southern Wisconsin at about 5.89 inches (normal near 2.08 inches, ~283% of normal); the last 7 days brought about 4.60 inches versus a normal near 0.84 inches. Recent rainfall and soil conditions look too wet for efficient combining across northwestern Iowa and southwestern Minnesota, northeastern Iowa, northern Illinois and southern Wisconsin, southwestern Iowa and northern Missouri, and southeastern Iowa, central Illinois and northern Indiana, so harvest delays and limited field access are likely until soils firm. Where prolonged wetness has encouraged mold or fungal growth on hybrid corn stalks, any stronger wind event would increase lodging and harvest-loss risk in vulnerable fields, so wind forecasts should be watched alongside soil trafficability. On a longer 30-day basis, soils remain especially saturated across northwestern Iowa and southwestern Minnesota (~6.7" in 30 days vs normal ~3.5"), northeastern Iowa, northern Illinois and southern Wisconsin (~6.7" in 30 days vs normal ~3.8"), and southwestern Iowa and northern Missouri (~5.9" in 30 days vs normal ~4.0"), which matches reports of very soft fields and delayed harvest. Forecast rainfall over days 1–5 averages near 0.82 inches, so drying windows may be interrupted rather than completely washed out.
