"Station: Des Moines INTP AP, IA". U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991–2020). National Oceanic and Atmospheric Administration. Retrieved June 26, 2021.
"Station: Moline Quad City INTL AP, IL". U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991–2020). National Oceanic and Atmospheric Administration. Retrieved June 25, 2021.
"Station: Sioux City Gateway AP, IA". U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991–2020). National Oceanic and Atmospheric Administration. Retrieved June 27, 2021.
Official records for Des Moines kept August 1878 to August 1939 at downtown and at Des Moines International since September 1939. For more information, see Threadex
Official precipitation records for the Quad Cities kept at the Weather Bureau Office (WBO) in Davenport, Iowa from July 1871 to December 1931, alternating between Quad City Int'l (KMLI) and the Davenport WBO from January 1932 to 17 February 1937, and remaining at KMLI since 18 February 1937. Temperature, snowfall, and snow depth records date to 1 January 1874, 1 August 1882, and 1 January 1901, respectively. For more information, see Threadex
Prior, Jean C. (1991) Landforms of Iowa. University of Iowa Press, Iowa City. "Landforms". Archived from the original on 2009-03-02. Retrieved 2008-06-09.. See also Calvin, Samuel (1904) Outline Map of the Drift Sheets of Iowa. Iowa Publication Co., Davenport.
Prior, Jean C. (1991) Landforms of Iowa. University of Iowa Press, Iowa City. "Landforms". Archived from the original on 2009-03-02. Retrieved 2008-06-09.. See also Calvin, Samuel (1904) Outline Map of the Drift Sheets of Iowa. Iowa Publication Co., Davenport.