The maximum of ice coverage on Lake Michigan each winter varies considerably. The maximum extent,expressed in percentage, depends on air temperatures, internal water currents, and wind speed/direction. Usually, the maximum extent occurs in February, but can happen in January or even early March. On occasions , Lake Michigan has been considered "frozen-over."
Ice coverage of 90% or more qualifies for a "frozen-over" designation. The winters that most agree qualify as frozen over are:
1976-1977, 1977-1978, 1978-1979, 1985-1986, 1990-1991, 1993-1994, 1995-1996, 2002-2003
Above is the link for ice coverages on Lake Michigan.
Recently with some hours of clear skies, satellite photographs show heavy ice cover around the lakes and lots of floating pack ice in the center of the lakes. Forecasters feel if the cold persists into February this year we could qualify for frozen over. Standing on the lake shore of either Lake Michigan or Lake Superior today you would only see ice as far as the horizon. That means ice stretches out from ten to thirty miles from the shoreline.