An old friend from high school has a farming operation in Iowa, about an hour east of Mason City. Following an extremely dry spring and summer, his farm received 17 inches of rain in August. This got me thinking about what records for the greatest rainfall over any 30-day period might be. For nearby Mason City, Iowa, the record is 16.92 inches ending June 21, 1954. My friend's recent rainfall would beat that.
Other record 30-day rainfall totals include: Fargo, 12.97 inches ending July 11, 2000; Grand Forks, 12.73 inches ending August 31, 1941; Bismarck, 15.61 inches ending July 27, 1993; Dickinson, 8.47 inches ending July 3, 1957; Minneapolis, 19.55 inches ending August 16, 1987; Rochester, 16.52 inches ending June 15, 2000; Duluth, 14.35 inches ending June 20, 2012; and Sioux Falls, 14.53 inches ending June 22, 2014. All of these maximum 30-day totals occurred during summer and include one remarkably heavy thunderstorm along with a generally wet pattern.