Iowa Weekly Growing Season Report
Preliminary weather summary for the week July 14-20, 2025
Widespread rainfall through the reporting period, heavy at various times and locations, added to a particularly wet July; a pocket of central Iowa observed two to three inches of above-normal totals. Temperatures moderated back to near normal over southeastern Iowa and slightly cooler northwest; the statewide average temperature was 72.3 degrees, 3.0 degrees below normal.
Sunday (13th) afternoon was pleasant with temperatures in the upper 70s and low 80s with a light southerly wind and ample sunshine. Morning lows on Monday (14th) held in the mid 60s with patchy fog across much of Iowa. Southerly flow pushed dew points into the upper 60s and low 70s with daytime temperatures in the low to mid 80s. Tuesday (15th) dawned with similar conditions as the previous morning with partly cloudy skies over eastern Iowa. Temperatures rose into the mid to upper 80s under persisting southerly winds and mostly sunny skies. Clouds increased over northwestern Iowa towards midnight as thunderstorms fired along a cold front in eastern South Dakota. The line pushed across Iowa overnight into Wednesday (16th), losing strength from central to eastern Iowa by daybreak. Much of western Iowa observed rainfall totals of at least 0.50 inch with most stations on the eastern periphery receiving a few tenths of an inch. Locations in northwest Iowa registered the highest totals with 1.11 inches in Westfield (Plymouth County) to 2.15 inches in Spencer (Clay County). Winds shifted to the northwest behind the front with daytime highs in the low 80s ahead of the front while the upper 60s and low 70s were observed west. Northerly winds continued into Thursday (17th) with overcast skies and lows in the mid 50s northwest to upper 60s southeast. With high pressure stabilizing the weather pattern, afternoon conditions started to improve as clouds broke with temperatures in the upper 60s and low 70s. Overnight lows into Friday (18th) varied from the mid 50s northeast to mid 60s southwest where clouds were present. Clouds expanded over the state through the daytime hours with afternoon highs in the 70s and southerly winds.
Clouds redeveloped across northern Iowa after midnight on Saturday (19th) as an east-west-oriented squall line sped southeast through Iowa. The line’s core thunderstorms became severe warned towards sunrise with a weak tornado reported near Gilbert (Story County). The cell then produced several reports of strong straight-line winds with a 71-mph gust a few miles southeast of the tornadic circulation. Several stations from north-central to eastern Iowa observed at least two inches of rain with 2.07 inches in Eagle Grove (Wright County) to 3.25 inches at Mount Auburn (Benton County). Nearly 100 stations collected an inch or more farther south and east of the highest totals with a statewide average of 0.61 inch. Skies gradually cleared through the day with a stationary front setting up over the middle of the state. Afternoon temperatures north of the boundary held in the upper 70s and low 80s with northerly winds. South of the front, winds were out of the south with mid-80 readings. Showers and thunderstorms formed along the front through the overnight hours into Sunday (20th). A concentrated line of heavier thunderstorms stretched from west-central Iowa southeast, with an expanded shield of moderate rain north and south. Numerous flash flood warnings were issued due to higher intensity rainfall on top of saturated soil profiles. Central to south-central Iowa saw the most significant totals with several stations accumulating nearly a month’s worth of rainfall; nearly 70 stations reported at least two inches with 4.1 inches in Allerton (Wayne County) and 4.49 inches in Osceola (Clarke County). The statewide average came in at 1.08 inches.
Weekly precipitation totals ranged from 0.09 inch in Corning (Adams County) to 5.14 inches in Sully (Jasper County). The statewide weekly average precipitation was 1.88 inches while the normal is 1.02 inches. Lamoni (Decatur County) reported the week’s high temperature of 91 degrees on the 16th, four degrees above normal. Fayette (Fayette County) reported the week’s low temperature of 50 degrees on the 18th, ten degrees below normal.
