year Superior Michigan Huron Erie Ontario All_Lakes year cover date cover date cover date cover date cover date cover date 1973 69.8 Feb-27 33.0 Feb-27 66.7 Feb-26 95.7 Feb-27 62.6 Feb-20 60.6 Feb-27 1973 1974 73.8 Feb-27 39.4 Feb-21 61.4 Feb-27 88.5 Feb-21 24.5 Jan-10 58.7 Feb-21 1974 1975 64.9 Feb-13 28.1 Jan-29 55.1 Feb-13 80.1 Feb-13 14.9 Feb-13 50.2 Feb-13 1975 1976 49.9 Mar-16 29.5 Feb-03 52.5 Jan-28 95.4 Feb-08 15.2 Feb-03 39.9 Feb-03 1976 1977 96.0 Feb-16 93.1 Feb-09 95.0 Feb-09 99.8 Feb-08 46.7 Feb-17 89.9 Feb-09 1977 1978 92.5 Mar-01 66.6 Feb-22 95.8 Mar-01 100.0 Feb-08 57.7 Feb-15 83.0 Feb-28 1978 1979 97.1 Feb-25 92.3 Feb-25 96.4 Feb-19 100.0 Feb-12 86.2 Feb-19 94.7 Feb-19 1979 1980 77.2 Mar-05 38.6 Feb-20 70.3 Mar-05 93.4 Mar-05 30.6 Feb-13 62.8 Mar-05 1980 1981 84.7 Feb-11 53.8 Jan-21 93.8 Feb-04 96.0 Jan-14 47.6 Jan-07 71.3 Feb-10 1981 1982 85.3 Mar-09 60.2 Feb-09 93.3 Mar-09 99.1 Feb-15 50.7 Jan-25 74.8 Mar-09 1982 1983 20.2 Feb-07 23.6 Feb-08 31.8 Feb-01 40.8 Feb-14 12.5 Feb-08 22.1 Feb-09 1983 1984 88.2 Mar-07 43.3 Feb-08 77.6 Mar-14 95.7 Jan-18 40.7 Jan-18 65.2 Feb-08 1984 1985 81.9 Mar-02 41.3 Feb-23 87.4 Feb-23 96.0 Feb-09 38.2 Feb-09 69.8 Feb-23 1985 1986 90.7 Feb-22 66.8 Feb-23 73.5 Feb-23 95.5 Feb-01 43.7 Feb-28 76.4 Feb-22 1986 1987 14.5 Jan-25 20.0 Feb-21 43.5 Feb-15 88.0 Feb-14 8.4 Feb-14 27.3 Feb-15 1987 1988 67.3 Feb-15 32.7 Feb-07 60.1 Mar-06 91.5 Feb-07 21.1 Jan-10 53.6 Feb-20 1988 1989 82.3 Mar-08 30.9 Mar-19 76.3 Mar-19 91.6 Feb-17 15.5 Mar-13 59.2 Mar-17 1989 1990 78.1 Mar-05 32.4 Jan-14 73.8 Mar-07 72.8 Mar-09 29.5 Feb-28 59.7 Mar-07 1990 1991 89.6 Mar-04 21.5 Jan-30 43.8 Feb-01 35.1 Feb-01 11.6 Feb-02 44.3 Mar-03 1991 1992 73.3 Mar-23 32.8 Feb-03 69.9 Mar-23 89.8 Feb-16 17.5 Feb-16 45.5 Mar-23 1992 1993 77.2 Mar-01 32.2 Feb-28 78.3 Feb-28 94.3 Feb-24 29.0 Feb-28 64.4 Feb-28 1993 1994 96.1 Feb-09 82.7 Feb-14 96.9 Mar-02 96.7 Feb-09 55.7 Feb-11 89.0 Feb-14 1994 1995 28.8 Mar-03 21.6 Feb-13 41.7 Mar-05 94.0 Feb-13 18.8 Feb-13 32.0 Mar-03 1995 1996 100.0 Mar-08 75.0 Feb-07 98.2 Feb-19 100.0 Feb-05 45.1 Feb-16 81.7 Mar-08 1996 1997 89.0 Mar-23 37.8 Feb-05 65.3 Feb-23 99.6 Feb-02 25.6 Feb-23 58.4 Feb-23 1997 1998 11.1 Jan-16 15.1 Feb-06 28.6 Feb-06 5.4 Jan-23 6.2 Jan-30 14.0 Feb-06 1998 1999 18.3 Feb-23 23.0 Jan-15 36.0 Mar-09 74.8 Jan-15 17.9 Mar-09 26.6 Jan-15 1999 2000 33.5 Feb-18 27.2 Jan-28 41.9 Feb-18 90.7 Feb-01 22.3 Feb-01 34.8 Feb-18 2000 2001 46.7 Mar-12 29.5 Feb-22 45.7 Feb-19 94.0 Feb-12 17.9 Feb-15 34.4 Feb-12 2001 2002 10.3 Mar-17 12.4 Mar-07 26.1 Mar-04 14.4 Jan-03 4.0 Jan-10 11.8 Mar-04 2002 2003 95.5 Mar-04 48.0 Mar-10 96.2 Mar-08 95.7 Jan-27 49.6 Feb-27 80.2 Mar-03 2003 2004 52.2 Feb-19 36.4 Feb-05 64.5 Feb-19 95.4 Feb-02 38.5 Jan-29 51.9 Feb-19 2004 2005 54.5 Mar-17 29.4 Jan-24 58.9 Mar-09 93.0 Feb-07 37.8 Jan-31 44.2 Mar-17 2005 2006 16.7 Mar-02 16.1 Feb-20 32.2 Mar-02 21.9 Mar-02 14.2 Mar-02 20.4 Mar-02 2006 2007 51.8 Mar-08 37.2 Mar-08 71.4 Mar-08 95.8 Feb-19 23.8 Mar-08 55.2 Mar-08 2007 2008 62.7 Mar-10 33.5 Feb-21 59.5 Mar-17 93.4 Mar-10 14.0 Mar-10 55.0 Mar-10 2008 2009 93.6 Mar-02 52.3 Jan-29 85.1 Mar-02 95.5 Feb-05 25.9 Feb-05 74.6 Mar-02 2009 2010 27.3 Feb-22 23.5 Feb-08 37.0 Feb-18 93.1 Feb-08 13.1 Feb-08 29.6 Feb-08 2010 2011 33.6 Apr-02 29.4 Feb-11 63.8 Feb-24 95.8 Feb-01 31.1 Feb-24 40.1 Feb-12 2011 2012 8.2 Jan-22 16.7 Jan-21 23.1 Mar-05 13.9 Jan-21 1.9 Feb-17 12.9 Jan-22 2012 2013 38.6 Feb-17 24.4 Feb-18 47.8 Feb-18 83.7 Feb-22 15.6 Feb-23 38.4 Feb-18 2013 2014 95.8 Mar-03 93.1 Mar-08 96.1 Mar-06 96.1 Mar-06 60.8 Mar-06 92.3 Mar-06 2014 2015 95.7 Feb-28 72.9 Feb-27 96.4 Mar-06 98.1 Feb-18 82.4 Feb-18 88.8 Mar-01 2015 2016 22.7 Feb-14 26.8 Feb-14 48.0 Feb-14 78.7 Feb-15 23.5 Feb-14 33.8 Feb-15 2016 2017 18.7 Mar-04 18.2 Jan-18 35.4 Mar-14 35.5 Feb-08 5.8 Mar-16 19.4 Mar-27 2017 2018 77.2 Feb-11 51.3 Feb-11 81.4 Feb-11 95.1 Feb-09 24.7 Jan-17 69.0 Feb-11 2018 2019 94.9 Mar-08 55.8 Mar-08 95.7 Mar-09 94.3 Mar-02 39.8 Mar-01 80.9 Mar-09 2019 2020 22.6 Feb-17 17.2 Feb-21 32.1 Mar-01 15.9 Feb-29 10.7 Feb-11 19.5 Feb-21 2020 2021 50.6 Feb-19 33.3 Feb-18 48.3 Feb-20 85.7 Feb-20 20.6 Feb-18 45.8 Feb-19 2021 2022 79.5 Mar-15 37.5 Feb-14 67.2 Feb-26 93.8 Jan-31 29.4 Feb-06 56.1 Feb-26 2022 2023 19.8 Feb-24 21.5 Feb-04 34.4 Feb-24 40.2 Feb-05 16.4 Feb-04 21.6 Feb-04 2023