August 2026 Overview – Midwestern Regional Climate Center

Temperature

The average August temperature for the Midwest was 71.8°F, which was 0.9°F above the 1991-2020 normal (Figure 1). Monthly average temperatures were 1 to 6°F above normal in the southwestern portion of the region, with temperatures closer to normal across the central and upper Midwest (Figure 2). Statewide average temperatures ranged from 0.3°F above normal in Ohio and Minnesota to 2.1°F above normal in Missouri. The first week of the month started cooler than normal before a large-scale weather pattern shift ushered in above-normal temperatures for the middle half of the month (Figure 3). The far lower Midwest—including southern Missouri, southern Illinois, and western Kentucky—had 8 consecutive days from about August 9-16 where the heat index exceeded 100°F, prompting widespread extreme heat warnings. Areas further north, in the central and upper Midwest, had elevated temperatures, but not extreme heat or humidity. Temperatures briefly moderated in late August, with near- to slightly below-normal temperatures in the east and near- to slightly above-normal temperatures in the west, before hot and humid weather blanketed the Midwest in the closing days of the month. There were no notable monthly station or statewide temperature records for August. The average summer (June-August) temperature for the Midwest was 1.2°F above normal (Figure 4).

Precipitation

August precipitation totaled 4.01 inches for the Midwest, which was 0.34 inches above normal, or about 109 percent of normal (Figure 1). Across the upper Midwest and southwest Missouri, precipitation was 10-75 percent of normal for August, while the central and eastern Midwest had precipitation that was 150-400 percent of normal for the month (Figure 5). Statewide precipitation totals ranged from 1.47 inches below normal in Minnesota to 3.5 inches above normal in Indiana. Final rankings indicate that Indiana and Ohio had their wettest August on record, and Illinois tied its 9th wettest on record. The large-scale weather pattern throughout the first three weeks of August brought repeated rain and storms to the central Midwest, with extremely high rainfall along an axis from central Iowa to eastern Ohio. The most extreme rainfall occurred from August 11-17 (Figure 6), producing a wide area of 6 to 14 inches that led to deadly flash and river flooding (additional details below). Conversely, those three weeks were extremely dry from central Minnesota to northern Michigan, and also in southwest Missouri. The closing week of August was dry region-wide, except for the eastern half of Michigan. New monthly precipitation records were set for numerous locations across Indiana and Ohio, and much of the central Midwest had a top 10 wettest August (Figure 7). New Castle, Indiana, accumulated 17.72 inches, smashing the previous August record set back in 1979 by nearly 8 inches. New Lexington, Ohio, measured 15.4 inches for the month, which broke the previous August record set in 1979 by over 5 inches. In Danville, IL, where records date back to 1895, a new August total was set with 13.98 inches. Conversely, Stambaugh in Michigan’s western Upper Peninsula, with records dating back 127 years, had its 2nd driest August with just 0.44 inches. The Minneapolis area had its 4th driest August since 1895, with just 0.46 inches. In southwest Missouri, Lamar had its 5th driest August in 133 years with just 0.22 inches for the month. Summer (June-August) precipitation for the Midwest was about 0.81 inches above normal (Figure 4), with the northwestern portion of the region 30-90 percent of normal and the central and lower Midwest largely 125-300 percent of normal (Figure 8).

Drought

Drought intensified across Wisconsin and Minnesota in August while the central and southeastern Midwest remained largely free of drought or abnormal dryness. Across Wisconsin, 70 percent of the state was in moderate to extreme drought by month’s end compared to just 34 percent in early August (Figure 9). In Minnesota, moderate to extreme drought affected 78 percent of the state. Southern Missouri also saw an expansion of drought, largely confined to the far southwest and southern portions of the state. Missouri ended August with about 27 percent of the state in moderate to severe drought and 16 percent abnormally dry.

Extreme Rainfall, Flooding, and Damaging Winds – August 11-17

A stalled frontal boundary draped across the central US enabled multiple rounds of intense thunderstorms to move from Iowa to Ohio from August 11-17, resulting in destructive winds, extreme rainfall totals, and flash and river flooding. This active pattern began with a derecho (a widespread, long-lived windstorm) on August 11 that brought 50-90 mph winds from eastern Iowa to Indiana, along with torrential rainfall (Figure 10). In northwest Indiana, peak winds reached nearly 100 mph, leaving residents in Gary in a weeks-long power outage. Daily rain and storms continued for the next week, leaving a wide swath of 6 to 14 inches of rain across the central US over the 7-day period. East-central Indiana was at the epicenter of the flood disaster resulting from rainfall that exceeded the 1000-year event threshold, with at least 7 fatalities, major damage to roads and bridges, and flooded neighborhoods and homes requiring emergency evacuation and rescue. New Castle, Indiana, picked up 7.74 inches on August 12 and 3.49 inches on August 13, which means they accumulated 25% of their average annual rainfall in just two days. A portion of Interstate 70 in Wayne County, Indiana, collapsed as rising water overtook the westbound lanes. In central Indiana, a 4-lane, divided suburban parkway serving as a principal arterial roadway in Carmel collapsed. Early estimates of Indiana-wide property damage from the flooding range from $550 million to $5 billion. In southeast Ohio, New Lexington measured 6.65 inches of rain in just two days, from August 11-12, with an additional 3.9 inches on August 16. Rising floodwaters required more than 50 overnight rescues in the small community as homes became inundated.