Month of September in Iowa One for the Record Books

(Des Moines) State Climatologist Dr. Justin Glisan has reported that Iowa received an average of eight-tenths of an inch of rainfall for September, making it the driest September on record preliminarily in the 152 years of recorded data.

Dr. Glisan noted that the state’s southwest region received only 30 percent of average precipitation, one to three inches below normal. In addition, temperatures in southwest Iowa averaged two and a half degrees above average, while the entire state averaged three degrees above average. He says a prominent ridge stationed over the central portion of the United States steered Hurricane HELENE to the mid-Atlantic states, where 17 to 25 inches of rain fell in Ashville, North Carolina. Glisan says the active tropical season is helping to block the west-to-east flow across the U.S. and also cutting off the Gulf of Mexico moisture gate.

Dr. Glisan also mentioned that despite the warm and dry conditions in September 2024, it remains in the top 25 wettest years statewide through August. However, the recent warm and dry conditions have led to an expansion of the state’s abnormally dry (D0) conditions. While recent rains in southwest Iowa have eased the D0 conditions in some areas, D1 drought conditions have emerged in Fremont, Pottawattamie, and Shelby counties.

Glisan says the warm and dry conditions are forecast to persist through mid-October.