DES MOINES — A parade of thunderstorms dumped nearly three times the normal weekly rainfall across Iowa, sharply limiting fieldwork but leaving the state’s corn and soybean crops in strong condition, according to the latest Iowa Crop Progress and Condition Report released Monday, August 17, 2026.
Iowa farmers had just 3.3 days suitable for fieldwork during the week ending August 16 as repeated rounds of rain crossed the state. The Iowa Department of Agriculture and Land Stewardship described it as the wettest week of the growing season.
Statewide rainfall averaged 2.60 inches for the week, compared with a normal 0.88 inch. Totals varied dramatically, ranging from just 0.36 inch at New Market in Taylor County to a whopping 9.45 inches at Wapello.
The wet weather boosted soil moisture across much of Iowa. Topsoil moisture was rated 4% very short, 15% short, 64% adequate and 17% surplus. Subsoil moisture was rated 5% very short, 21% short, 63% adequate and 11% surplus.
Despite the heavy rain and severe weather, Iowa’s major crops continued to develop ahead of or near normal schedules.
Corn silking reached 99%, one percentage point ahead of last year. Eighty-three percent of the crop had reached the dough stage, six percentage points ahead of last year, while 26% had reached the dent stage, one point ahead of last year.
Iowa’s corn crop was rated 78% good to excellent.
Soybean blooming reached 96%, matching last year, while 82% of soybeans were setting pods. Soybean condition was also rated 78% good to excellent.
Oat harvest continued to move toward completion, with 96% of the crop harvested — six percentage points ahead of last year.
Pasture condition was rated 67% good to excellent.
Secretary of Agriculture Mike Naig said widespread rainfall, severe thunderstorms and an eastern Iowa derecho highlighted the week, while better weekend weather helped draw crowds to the Iowa State Fair.
“Last week brought widespread rainfall across much of Iowa, including several rounds of thunderstorms and a derecho that developed in eastern Iowa before continuing across parts of the eastern Corn Belt,” Naig said.
SEVERE STORMS HAMMER IOWA
The week’s weather was dominated by what meteorologists described as a “Ring of Fire” pattern, with high pressure over the southern United States steering repeated thunderstorm complexes across Iowa.
One of the most significant rounds arrived Tuesday morning, August 11, when storms developed across northern Iowa and strengthened while moving east.
A 75-mph wind gust was recorded at Independence in Buchanan County as a powerful line of storms intensified into what was later classified as a derecho. The system continued for hundreds of miles across the Ohio Valley before eventually dissipating in Virginia.
Two EF-1 tornadoes also developed near Greeley in Delaware County, damaging vegetation and outbuildings.
Heavy rain accompanied the severe weather. Belle Plaine recorded 2.48 inches, while North Liberty received 2.33 inches.
Another line of severe storms moved into western Iowa early Wednesday before crossing the state, followed by yet another large thunderstorm complex Thursday.
The Thursday system stretched across much of Iowa and prompted several severe thunderstorm and tornado warnings in western and central sections of the state. No tornadoes were confirmed from that round.
Rainfall piled up quickly.
During one 36-hour period, nearly 50 Iowa weather stations measured at least 2 inches of rain. Gilbert recorded 3.05 inches, while Schleswig received 4.31 inches.
More thunderstorms formed Thursday night into Friday, producing flash flood warnings as storms repeatedly moved over some of the same areas.
By Saturday morning, several stations reported extraordinary rainfall totals, including 3.06 inches at Pella, 5.01 inches at Norwalk and 5.31 inches at Wapello.
Additional storms struck southeastern Iowa Saturday, producing 1.84 inches at Mount Union, 3.05 inches at Burlington and 3.49 inches at Fort Madison.
IOWA RUNS WARM DESPITE STORMS
The week was also warmer than normal overall.
Iowa’s statewide average temperature was 76.7 degrees, or 4.8 degrees above normal.
Lamoni recorded the week’s highest temperature at 95 degrees on August 11, nine degrees above normal.
Greenfield recorded the state’s coolest temperature for the week at 48 degrees on August 12, which was 15 degrees below normal.
The USDA National Agricultural Statistics Service releases Iowa’s Crop Progress and Condition Report weekly from April through November, while the Iowa Department of Agriculture and Land Stewardship provides the accompanying statewide weather summary.