Iowa's Record Precipitation
This official 24-hour rainfall record for the state of Iowa is 13.18 inches, reported from a station in Atlantic, IA (Cass County) on the morning of June 14, 1998.
A small cluster of thunderstorms formed over the southwest counties during the early morning hours, and seven inches of the rain fell in 4.5 hours between 0830 and 1300 CST. The major flooding event was the result of a robust upper-level system combined with a warm front, causing heavy rain over soils were already saturated before the event took began.
Source: NOAA.gov
Did you know?
Previously reported record of 16.70 inches in Decatur Co. on August 5-6, 1959 is likely valid, but was estimated from a post-event survey observation. A 13.52 inch observation was made at Atlantic 5SW on June 14, 1998, but it is likely that the observation covered more than a 24-hr period.