Iowa Weekly Growing Season Report
Preliminary weather summary for the week June 9-15, 2025
An unsettled weather pattern persisted across Iowa over the reporting period with multiple rounds of showers and thunderstorms. Even though rainfall was widespread, weekly totals were still below normal for much of Iowa. Temperatures were generally near-normal to a degree above normal for most of Iowa with a statewide average temperature of 70.2 degrees, 0.4 degree above normal.
Showers pushed across southern Iowa on Sunday (8th) afternoon as a cold front dropped through the state. Clear skies over northern Iowa helped push temperatures into the mid 70s. Rainfall totals where generally under 0.20 inch with most stations reporting less than 0.10 inch; a 0.21-inch-total was found in Murray (Clarke County). Winds shifted to the northwest on Monday (9th) morning with partly cloudy conditions developing through the daytime hours and highs in the 60s. Tuesday (10th) dawned with clear skies and patchy fog over portions of Iowa where winds were light; morning lows held in the 50s for most Iowa stations. Westerly winds persisted as highs warmed into the upper 80s and low 90s in northwestern Iowa with upper 70s southeast under sunny skies. A southerly shifting wind and temperatures in the 60s greeted Iowans on Wednesday (11th) morning with conditions quickly warming into the 80s by noon. A stationary front draped over northern Iowa was a forcing mechanism for strong to severe thunderstorms during the afternoon and evening hours. Several storms produced large hail and severe straight-line winds along a line from Rock Rapids (Lyon County) to Urbana (Benton County). There were numerous reports of crop and tree damage from larger hail and wind-driven hail. Moderate to heavy rain and training thunderstorms also brought significant totals to north-central Iowa; Nashua (Floyd County) observed 2.10 inches while Mason City (Cerro Gordo County) collected 3.22 inches. Many stations along the eastern and western periphery reported amounts in the 0.50 to 1.00-inch with lesser totals farther south.
Winds turned easterly into Thursday (12th) with some lingering showers in northern Iowa with otherwise clear conditions and temperatures in the 60s. Scattered thundershowers popped up from south-central to northeastern Iowa during the late afternoon into the nighttime hours. Several stations reported heavier amounts, varying from 1.02 inches in Davis City (Decatur County) to 2.20 inches in Osage (Mitchell County). Conditions stabilized on Friday (13th) with southeasterly winds and unseasonably warm temperatures in the upper 60s and low 70s. Cloud cover increased into the afternoon with daytime highs in the 80s statewide. A few isolated thunderstorms developed in north-central Iowa around sunset with showers moving over extreme southeastern Iowa; rain totals were under a few tenths of an inch. Overnight lows on Saturday (14th) were up to 10 degrees above normal, in the upper 60s and low 70s for several locations. With higher dewpoints and light winds, dense fog formed over much of the state through early morning. As temperatures warmed, showers and thunderstorms developed along a surface boundary from central to northwestern Iowa, where some cells became severe warned. The complex expanded over most of northern Iowa with the highest amounts in Hamilton County where two Webster City gauges collected 2.61 and 2.84 inches. Twenty five stations reported at least an inch with widespread 0.25-0.50-inch totals reported at 7:00 am on Sunday (15th); the statewide average was 0.38 inch.
Weekly rainfall ranged from no accumulation in eastern and western Iowa to 3.83 inches in Mason City. The statewide weekly average precipitation was 0.68 inch; the normal is 1.19 inches. Manchester (Delaware County) reported the week’s high temperature of 97 degrees on the 11th, 18 degrees above normal. Mount Ayr (Ringgold County) and Stanley (Buchanan County) reported the week’s low temperature of 43 degrees on the 10th, on average 15 degrees below normal.
