Iowa Weekly Growing Season Report
Preliminary weather summary for the week ending May 19 - May 25, 2025
Unseasonably cool and wet conditions were the headline of the reporting period with widespread, beneficial rain across much of Iowa; nearly 250-300% of normal rainfall was observed in central to eastern Iowa. Coupled with cloud cover and rain, conditions were six to 10 degrees below normal with the statewide average temperature at 55.0 degrees, 8.1 degrees below normal.
Easterly winds persisted through Sunday (18th) afternoon under sunny skies and highs in the upper 60s and low 70s. Cloud cover increased towards midnight as showers and a few thunderstorms pushed into southwest Iowa ahead of a low pressure center over the Dakotas. Rain totals at 7:00 am on Monday (19th) were in the 0.25 – 0.75 inch range across much of western Iowa with pockets over an inch near the Iowa-Nebraska border; Randolph (Fremont County) reported 1.10 inches while 1.55 inches was observed in Blencoe (Harrison County). A stronger disturbance moved into southern Iowa during the afternoon hours, where high temperatures were in the mid to upper 60s. Severe-warned thunderstorms crossed into Iowa from northern Missouri and sped northeast into late evening as showers and thunderstorms overspread much of Iowa. Several reports of hail were noted along I-35 with 2.00-inch diameter hail in Grand River (Decatur County) and Osceola (Clarke County). Light to moderate rain continued from central to northeastern Iowa into Tuesday (20th) morning with lows in the mid 40s northeast to upper 50s southwest. Additional stronger thunderstorms fired in eastern Iowa as the low pressure center transited into Wisconsin in the latter daytime hours. Nearly 85% of Iowa stations reported an inch or more with 70 stations collecting at least two inches, particularly along a swath of south-central to central Iowa and into eastern Iowa; Gilbert (Story County) registered 3.02 inches while Norwalk (Warren County) observed 4.76 inches. At a statewide average of 2.06 inches, these rain totals made up the bulk of the week’s rainfall.
Overcast skies remained through Wednesday (21st) with daytime highs in the low 50s north to low 60s south with gusty northwesterly winds. Light showers filtered into eastern Iowa, though totals were generally under a few tenths of an inch; Anamosa (Jones County) collected 0.20 inch with 0.31 inch in Park View (Scott County). Skies over western Iowa cleared into Thursday (22nd) morning, allowing lows to drop into the low to mid 40s. Highs rose into the 60s across much of the state as stubborn clouds and light northerly winds remained. Friday (23rd) was pleasant as mostly sunny skies, light winds and temperatures in the mid to upper 60s greeted Iowans ahead of Memorial Day weekend. Cloud cover and showers moved through western Iowa into the late evening and dissipated through the overnight hours. Northwest Iowa reported the highest totals with 0.55 inch in Orange City (Sioux City) with totals tapering off to a few tenths east and south. Saturday (24th) stayed cloudy for most of the day with temperatures in the low 60s to low 70s with light showers filling in across southern Iowa after sunset. The highest rain totals, between 0.21 – 0.42 inch, were isolated to Mills, Page and Pottawattamie counties as of Sunday (25th) morning.
Weekly rain totals ranged 0.49 inch in Sanborn (O’Brien County) to 4.99 inches in Grand River. The statewide weekly average rainfall was 2.10 inches; the normal is 1.10 inches. Several stations reported the week’s high temperature of 78 degrees on the 18th, on average five degrees above normal. Mason City (Cerro Gordo County) reported the week’s low temperature of 32 degrees on the 20th, 17 degrees below normal. Soil temperatures were in the upper 50s to low 60s statewide as of Sunday.
