October 2024 Overview – Midwestern Regional Climate Center

Temperature

The average October temperature for the Midwest was 56.0°F, which was 4.6°F above the 1991-2020 normal. Final rankings indicate the Midwest as a whole had the 9th warmest October on record (Figure 1). The entire Midwest was warmer than usual, with average temperatures ranging from 5-7°F above normal in the northwest to 1-3°F above normal in the southeast (Figure 2). Statewide average temperatures ranged from 6.3°F above normal in Minnesota to 2.3°F above normal in Kentucky (Figure 1). Final rankings indicate Minnesota and Iowa both had the 6th warmest October on record (Figure 3). Persistently high daytime maximum temperatures largely drove the above-normal monthly temperatures (Figure 4), while overnight minimum temperatures were fairly typical for October, except in the northwest, where overnight temperatures were up to a few degrees above normal (Figure 5). Green Bay, Wisconsin, had five separate days this month with temperatures reaching or exceeding 80°F, the third-greatest number of October days reaching this threshold in 137 years. With 17 days, Springfield, Missouri, had their second-greatest number of October days with temperatures at or above 80°F. Much of the region achieved its first freeze of the fall season in mid-October, effectively ending the growing season (Figure 6).

Precipitation

October precipitation totaled 1.14 inches for the Midwest, which was 1.96 inches below normal, or 37 percent of normal (Figure 1). Final rankings indicate the Midwest as a whole had its 9th driest October on record. The lack of October rainfall was widespread and severe regionwide. Only a narrow swath from northwest Missouri to east-central Wisconsin had near-normal precipitation (Figure 7). Elsewhere, precipitation was 2-4 inches below normal, with large portions of Indiana and Kentucky receiving less than 0.25 inches for the entire month (Figure 8). Statewide precipitation totals ranged from 0.99 inches below normal in Iowa to 3.50 inches below normal in Kentucky (Figure 1). Final rankings indicate that both Indiana and Kentucky had their 2nd driest October on record, and Ohio had its 7th driest (Figure 9). Numerous cities throughout the region had their driest October on record, including Jackson, Kentucky; Frankfort, Indiana; Mansfield, Ohio; and Milan, Minnesota. Dozens more locations had a top 10 driest month. Across the lower Midwest and large portions of Minnesota and Iowa, measurable precipitation (greater than 0.01 inches) was reported on just 1-4 days during the entire month (Figure 10).

Drought

The month ended with about 97 percent of the Midwest classified as abnormally dry or in drought, according to the U.S. Drought (USDM) map, which was about an 18 percent expansion compared to the start of October (Figure 11). Exceptional (D4) drought remained widespread across southeast Ohio, and extreme (D3) drought emerged in southwest Missouri. Moderate (D1) to severe (D2) drought blanketed the central and upper Midwest, while areas adjacent to the Ohio River were abnormally dry.

Severe Weather

The large-scale weather pattern for October was dominated by high-pressure systems that suppressed cloud formation, precipitation, and storm development for much of the region over much of the month. The pattern started to shift in the closing days of the month when a weather disturbance traversed the upper Midwest, surging warm, unstable air and strong southerly winds across the lower Midwest. When paired with the previous weeks of dry weather, this resulted in elevated fire risk from October 28-30. A single day of notable severe weather was observed on October 30 when damaging winds and isolated tornadoes were reported across Missouri, southern Iowa, and far western Illinois (Figure 12).