August 22-31, 2025

Temperatures

The final week of August was significantly cooler than the prior week(s). The entire Midwest observed below normal temperatures. Average temperatures were a widespread 5-10°F below normal (Figure 1). Across Minnesota, they were slightly less anomalous, albeit still 3-5°F below normal.

Minimum temperatures were up to 10°F below normal for the week along I-70 from western Ohio toward Missouri (Figure 2). The rest of the region was a solid 5-10°F below normal, save Minnesota, where minimum temperatures were 2-4°F below normal. Minimum temperatures were in the 40s as far south as Lexington, Kentucky, and St. Louis, Missouri. The cooler weather was noteworthy for its duration. Lexington observed three consecutive days of minimum temperatures less than 50°F from August 26-28, which was the first time minimum temperatures remained below 50°F for that long in August since records began in 1872. Similarly, Springfield, Illinois, observed minimum temperatures less than 50°F on three consecutive days, August 25-27, for only the third time since records began there in 1879.

Maximum temperatures were 4-8°F below normal for most of the region (Figure 3). While maximum temperatures were not as anomalous as minimum temperatures, they were still notably cooler than normal. In Lamar, Missouri, a station with records dating back to 1890 observed a maximum temperature of 70°F on August 26, the coldest August high temperature since 2012.

Precipitation

With cooler temperatures and high pressure in control, a major drying trend occurred during the final week of the month. The southern half of the region observed no precipitation. There was some light precipitation across the Upper Midwest, but it was mainly confined to Michigan’s UP (Figure 4).

With drier conditions, drought expanded slightly across the region. As of August 26, D0 (abnormally dry) was up to nearly 30 percent coverage, a nearly 10 percent increase over the prior week. D1 (moderate drought) was up to 4.5 percent of the region, now encompassing far southern parts of the region, as well as eastern Illinois and mid-Michigan (Figure 5).

Severe Weather

There were a few storm reports across the region this week, with drier and cooler conditions in place. On August 27, a hail event took place over southern Minnesota. Several locations reported 1-2 inch hail, or roughly quarter-size to half-dollar-size hail. An isolated landspout occurred in Goodhue County, Minnesota, on August 29.