August 2025 Overview – Midwestern Regional Climate Center

Temperature

The average August temperature for the Midwest was 70.4°F, which was 0.5°F below the 1991-2020 normal (Figure 1). Average temperatures across most of the region were near normal for August, with scattered patches of slightly below-normal temperatures across the lower Midwest (Figure 2). Statewide average temperatures ranged from 0.3°F above normal in Minnesota to 1.2°F below normal in Ohio. August temperatures fluctuated widely from week to week. Across the region, the month started and closed with notably cool temperatures for this time of year, with mid-month temperatures surging to 3 to 6°F above normal from August 8-21. Across the lower Midwest, temperatures peaked in the upper 90s to low 100s in mid-August before dipping into the mid-40s late in the month.

In Springfield, Missouri, daily high temperatures peaked at or above 95°F for six consecutive days from August 14-19. Conversely, a handful of isolated locations across Michigan’s Upper Peninsula briefly had their first freezing temperatures since spring, which is several weeks earlier than usual. Across the region, overnight low temperatures for the month showed a northwest to southeast divide (Figure 3). Minimum monthly temperatures were up to 3 degrees above normal across Minnesota and down to 3 degrees below normal across the Ohio River Valley. In northeast Minnesota, Tower had its 5th warmest monthly low temperatures for August in 70 years of recordkeeping (Figure 4). Conversely, Steubenville in eastern Ohio had its 7th coldest monthly low temperatures for August dating back 75 years (Figure 5). The average summer (June-August) temperature for the Midwest was 1.1°F above normal (Figure 6), with most locations east of the Mississippi River up to 1 to 2°F above normal (Figure 7). This summer had the 7th warmest average minimum temperature on record, tying 2018 and 2005 (61.5°F).

Precipitation

August precipitation totaled 2.27 inches for the Midwest, which was 1.4 inches below normal, or 62 percent of normal (Figure 1). Most of the Midwest had notable precipitation deficits, except for northern Michigan and a narrow swath along an axis from west-central Minnesota to southeast Wisconsin, where precipitation was 100-200 percent of normal (Figure 8). Most of the lower Midwest had less than 50 percent of normal for August, with areas in southern Illinois and southern Ohio seeing less than 10 percent of normal. Statewide precipitation totals ranged from 0.19 inches below normal in Wisconsin to 2.74 inches below normal in Missouri. Final rankings indicate Kentucky and Ohio had their driest August on record, and Missouri and Illinois had their 3rd and 6th driest August on record, respectively. Numerous individual locations across the lower Midwest had a top-five driest August (Figure 9) as precipitation departures for the month reached 2 to 4 inches below normal (Figure 10). In contrast, numerous long-running weather stations in southern Minnesota, northeast Iowa, and southern Wisconsin had a top 10 wettest August (Figure 11). Decorah, in northeast Iowa, measured 13.61 inches of August precipitation, which is the 2nd wettest in 124 years. Milwaukee, Wisconsin, collected 8.94 inches in August, which was over 5 inches above normal and the 2nd wettest in 154 years. Remarkably, most of Milwaukee’s monthly rain fell in a single event from August 9-11, and more about that is noted below. Summer (June-August) precipitation for the Midwest was about 0.6 inches above normal (Figure 6), with the northwest portion of the region 100-175 percent of normal and the southeast mixed with areas generally within 25 percent above or below normal (Figure 12).

Drought

After several months of improvement, abnormally dry and drought conditions were reintroduced across the lower Midwest throughout August. Conditions largely remained unchanged across the upper Midwest, with lingering pockets of moderate (D1) to severe (D2) drought in central Michigan and most areas across Wisconsin, Minnesota, and Iowa free of dryness or drought. Overall, the Midwest concluded August with about 25 percent of the region dry and just over 4 percent in moderate (D1) drought (Figure 13).

August 9-11, 2025: Historic rainfall across southeast Wisconsin

Persistent heavy rainfall affected a multi-county area in and around Milwaukee, Wisconsin, from August 9-11 (Figure 14). A wide swath of 6 to 12 inches of rainfall caused numerous streams and rivers to overflow their banks, and record crests occurred on the Menomonee River, Milwaukee River, and Root River. Flash flooding stranded and flooded vehicles at the Wisconsin State Fair, along streets, and in parking garages throughout Milwaukee and Waukesha counties. Major interstate highways were closed due to flooding, and emergency responders conducted hundreds of rescues throughout the area. Several weather stations reported 24-hour rainfall totals that exceeded the current statewide record of 11.72 inches, and further investigation for a new record rainfall event is ongoing.