View the ice-over and ice-out dates, and duration of ice cover, for Lake Mendota dating back to 1852.
Annual Duration of Ice Cover
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Longest Duration
161 days
(1880-81)
Shortest Duration
21 days
(2001-02)
Average Duration
102 days
Five-Year Running Average
75 days
Freeze and Thaw Dates
| Winter | Freeze-Over Date | Thaw Date | Days of Ice Cover |
|---|---|---|---|
| 2023-24 | January 15 | February 28 | 44 |
| 2022-23 | December 25 | April 2 | 98 |
| 2021-22 | January 7 | April 2 | 85 |
| 2020-21 | January 3 | March 20 | 76 |
| 2019-20 | January 12 | March 22 | 70 |
| 2018-19 | January 10 | March 31 | 86 |
| 2018-19 | December 15 | December 21 | |
| 2017-18 | December 27 | March 31 | 94 |
| 2016-17 | January 1 | March 7 | 65 |
| 2015-16 | January 11 | March 13 | 62 |
| 2014-15 | January 2 | April 3 | 91 |
| 2013-14 | December 16 | April 12 | 117 |
| 2012-13 | January 14 | April 11 | 87 |
| 2011-12 | January 14 | March 11 | 57 |
| 2010-11 | December 15 | April 3 | 109 |
| 2009-10 | December 29 | March 26 | 87 |
| 2008-09 | December 16 | March 23 | 97 |
| 2007-08 | December 26 | April 10 | 106 |
| 2006-07 | January 20 | March 27 | 66 |
| 2005-06 | December 19 | March 24 | 95 |
| 2004-05 | December 25 | April 5 | 101 |
| 2003-04 | January 7 | March 27 | 80 |
| 2002-03 | January 4 | April 3 | 89 |
| 2001-02 | March 4 | March 15 | 21 |
| 2001-02 | January 2 | January 12 | |
| 2000-01 | December 13 | April 7 | 115 |
| 1999-00 | January 14 | March 7 | 53 |
| 1998-99 | December 30 | March 21 | 82 |
| 1997-98 | January 11 | February 27 | 47 |
| 1996-97 | December 20 | April 1 | 102 |
| 1995-96 | December 10 | April 7 | 119 |
| 1994-95 | January 6 | March 21 | 74 |
| 1993-94 | December 27 | March 31 | 94 |
| 1992-93 | December 24 | April 11 | 108 |
| 1991-92 | December 18 | March 26 | 99 |
| 1990-91 | December 26 | March 24 | 88 |
| 1989-90 | December 12 | March 15 | 93 |
| 1988-89 | December 29 | April 5 | 97 |
| 1987-88 | January 2 | March 29 | 87 |
| 1986-87 | December 13 | March 12 | 89 |
| 1985-86 | December 14 | March 31 | 107 |
| 1984-85 | January 2 | March 27 | 85 |
| 1984-85 | December 25 | December 26 | |
| 1983-84 | December 19 | April 8 | 111 |
| 1982-83 | January 13 | March 8 | 54 |
| 1981-82 | December 28 | April 3 | 96 |
| 1980-81 | December 20 | March 23 | 93 |
| 1979-80 | December 29 | April 6 | 99 |
| 1978-79 | December 25 | April 19 | 118 |
| 1978-79 | December 10 | December 13 | |
| 1977-78 | December 10 | April 11 | 123 |
| 1977-78 | December 7 | December 8 | |
| 1976-77 | December 3 | March 28 | 115 |
| 1975-76 | December 27 | March 24 | 88 |
| 1974-75 | January 2 | April 19 | 107 |
| 1973-74 | December 21 | April 5 | 105 |
| 1972-73 | December 7 | March 14 | 97 |
| 1971-72 | January 5 | April 19 | 105 |
| 1970-71 | December 24 | April 13 | 110 |
| 1969-70 | December 16 | April 8 | 113 |
| 1968-69 | December 25 | April 10 | 108 |
| 1968-69 | December 17 | December 19 | |
| 1967-68 | December 27 | March 27 | 91 |
| 1966-67 | December 26 | April 3 | 98 |
| 1965-66 | January 11 | March 17 | 65 |
| 1964-65 | December 15 | April 14 | 120 |
| 1963-64 | December 20 | April 11 | 113 |
| 1962-63 | December 12 | April 3 | 112 |
| 1961-62 | December 16 | April 12 | 117 |
| 1960-61 | December 19 | April 6 | 108 |
| 1959-60 | December 29 | April 12 | 105 |
| 1958-59 | December 9 | April 14 | 126 |
| 1957-58 | December 30 | April 4 | 95 |
| 1956-57 | December 14 | April 4 | 111 |
| 1955-56 | December 12 | April 4 | 114 |
| 1954-55 | January 2 | April 4 | 92 |
| 1953-54 | December 30 | March 25 | 85 |
| 1952-53 | December 30 | March 21 | 81 |
| 1951-52 | December 16 | April 8 | 114 |
| 1950-51 | December 11 | April 12 | 122 |
| 1949-50 | December 23 | April 11 | 109 |
| 1948-49 | December 24 | March 30 | 96 |
| 1947-48 | December 21 | April 3 | 104 |
| 1946-47 | December 30 | April 10 | 101 |
| 1945-46 | December 13 | March 21 | 98 |
| 1944-45 | December 18 | March 20 | 92 |
| 1943-44 | December 16 | April 8 | 114 |
| 1942-43 | December 7 | April 2 | 116 |
| 1941-42 | January 3 | March 26 | 82 |
| 1940-41 | January 5 | April 11 | 96 |
| 1939-40 | January 2 | April 16 | 105 |
| 1938-39 | December 28 | April 4 | 97 |
| 1937-38 | December 7 | March 22 | 105 |
| 1936-37 | January 5 | April 13 | 121 |
| 1936-37 | December 7 | December 30 | |
| 1935-36 | December 20 | March 30 | 101 |
| 1934-35 | December 24 | March 28 | 94 |
| 1933-34 | December 25 | March 26 | 91 |
| 1932-33 | December 10 | April 4 | 115 |
| 1931-32 | January 30 | April 4 | 65 |
| 1930-31 | December 16 | March 24 | 98 |
| 1929-30 | December 3 | March 20 | 107 |
| 1928-29 | December 21 | March 27 | 96 |
| 1927-28 | December 17 | April 1 | 106 |
| 1926-27 | December 6 | March 19 | 103 |
| 1925-26 | December 16 | April 19 | 124 |
| 1924-25 | December 19 | April 3 | 105 |
| 1923-24 | January 1 | April 14 | 104 |
| 1922-23 | December 16 | April 20 | 125 |
| 1921-22 | December 25 | March 31 | 96 |
| 1920-21 | December 25 | March 16 | 81 |
| 1919-20 | December 9 | March 28 | 110 |
| 1918-19 | January 3 | March 26 | 82 |
| 1917-18 | December 11 | April 5 | 115 |
| 1916-17 | December 16 | April 11 | 116 |
| 1915-16 | December 28 | April 8 | 102 |
| 1914-15 | December 16 | April 10 | 115 |
| 1913-14 | January 12 | April 10 | 88 |
| 1912-13 | December 24 | April 2 | 99 |
| 1911-12 | December 28 | April 14 | 108 |
| 1910-11 | December 9 | March 20 | 101 |
| 1909-10 | December 18 | March 26 | 98 |
| 1908-09 | December 22 | April 7 | 106 |
| 1907-08 | January 1 | March 24 | 83 |
| 1906-07 | December 20 | March 24 | 94 |
| 1905-06 | January 1 | April 8 | 97 |
| 1904-05 | December 14 | April 1 | 108 |
| 1903-04 | December 13 | April 17 | 126 |
| 1902-03 | December 25 | March 24 | 89 |
| 1901-02 | December 15 | March 30 | 105 |
| 1900-01 | December 25 | April 11 | 107 |
| 1899-00 | December 27 | April 17 | 111 |
| 1898-99 | December 9 | April 18 | 130 |
| 1897-98 | December 17 | March 27 | 100 |
| 1896-97 | December 21 | April 10 | 110 |
| 1895-96 | January 5 | April 5 | 91 |
| 1894-95 | December 28 | April 8 | 101 |
| 1893-94 | December 4 | March 15 | 101 |
| 1892-93 | December 16 | April 7 | 112 |
| 1891-92 | December 27 | April 2 | 97 |
| 1890-91 | December 26 | April 16 | 111 |
| 1889-90 | January 14 | March 30 | 75 |
| 1888-89 | January 2 | March 31 | 88 |
| 1887-88 | December 24 | April 15 | 113 |
| 1886-87 | December 5 | April 15 | 131 |
| 1885-86 | December 12 | April 19 | 128 |
| 1884-85 | December 17 | April 20 | 124 |
| 1883-84 | December 18 | April 15 | 119 |
| 1882-83 | December 10 | April 13 | 124 |
| 1881-82 | January 2 | March 21 | 78 |
| 1880-81 | November 23 | May 3 | 161 |
| 1879-80 | December 17 | March 25 | 99 |
| 1878-79 | December 21 | April 12 | 112 |
| 1877-78 | January 6 | March 9 | 62 |
| 1876-77 | December 8 | April 17 | 130 |
| 1875-76 | January 10 | April 10 | 91 |
| 1874-75 | December 10 | April 15 | 126 |
| 1873-74 | November 29 | April 14 | 136 |
| 1872-73 | November 30 | April 23 | 144 |
| 1871-72 | December 19 | April 23 | 126 |
| 1870-71 | December 24 | April 2 | 99 |
| 1869-70 | December 2 | April 12 | 131 |
| 1868-69 | December 10 | April 16 | 127 |
| 1867-68 | December 12 | March 31 | 110 |
| 1866-67 | December 18 | April 20 | 123 |
| 1865-66 | December 14 | April 18 | 125 |
| 1864-65 | December 8 | April 5 | 118 |
| 1863-64 | December 18 | April 21 | 125 |
| 1862-63 | December 26 | April 9 | 104 |
| 1861-62 | December 2 | April 13 | 132 |
| 1860-61 | December 14 | April 10 | 117 |
| 1859-60 | December 7 | March 26 | 110 |
| 1858-59 | December 8 | March 14 | 96 |
| 1857-58 | November 25 | March 26 | 121 |
| 1856-57 | December 6 | May 6 | 151 |
| 1855-56 | December 18 | April 14 | 118 |
| 1854-55 | – | – | |
| 1853-54 | December 27 | – | |
| 1852-53 | – | April 5 |