Water level The lake fluctuates from month to month with the highest lake levels typically occurring in summer. The normal high-water mark is above datum ('). In October 1986, Lakes Michigan and Huron reached their highest level at above datum.Monthly bulletin of Lake Levels for The Great Lakes; September 2009; U.S. Army Corps of Engineers, Detroit District The monthly average high-water records were broken for several months in a row in 2020.
Water level The lake fluctuates from month to month with the highest lake levels typically occurring in summer The normal high-water mark is above datum (') In October 1986 Lakes Michigan and Huron reached their highest level at above datumMonthly bulletin of Lake Levels for The Great Lakes; September 2009; US Army Corps of Engineers Detroit District The monthly average high-water records were broken for several months in a row in 2020