Joe Foss Field in Sioux Falls totalled 2.15 inches of rain on October 6th, 2008. This smashes the previous extreme for total rainfall for the date. The previous record was 1.09 inches in 1982.
Huron, SD did not quite make a record. Total rainfall for the Huron regional airport for October 6th was 1.37 inches. The very old record of 1.79 inches for the date of October 6th still stands, set back in 1882!
Sioux Gateway in Sioux City received 0.68 inches of rain on October 6th. Their record daily rainfall for the 6th of October is 2.02 inches set back in 1903.