Minnesota's Historical Lake Ice-Out Dates

The definition of lake ice-out varies from lake to lake, and individual to individual. For some, ice-out occurs only when the lake is completely free of ice. For others, ice-out is defined as the moment when navigation is possible from point A to point B. And yet for others, ice-out is when 90 percent of the lake is ice free. Due to the variable definitions of this rather subjective observation, the State Climatology Office attempts to contact the same individuals each year to maintain a consistent record. The table below summarizes historical lake ice-out averages and extremes for Minnesota lakes with 10 or more years of record.

In addition to differences in ice-out observation techniques, the variable period of record and variable length of record makes lake to lake comparisons of averages and extremes problematic. Differences in lake size, lake depth, and lake geometry also generate a large amount of variability among lakes in close proximity. In spite of these inherent problems, the tables below demonstrate a recognizable pattern in average lake ice-out across Minnesota, and also call attention to years of very early or very late lake ice-out.

Northwest

Lake Name	County	Average Ice-Out	Earliest Ice-Out	Latest Ice-Out	Years of Data
Bronson	Kittson	April 15	April 1, 2000	April 27, 1996	22
Big Cormorant	Becker	April 11	April 5, 2000	May 2, 1997	11
Detroit	Becker	April 20	March 23, 1910	May 17, 1950	113
Red (Lower)	Beltrami	April 27	April 12, 2000	May 17, 1996	18
Sallie	Becker	April 18	April 3, 2000	May 7, 1979	30

North Central

Lake Name	County	Average Ice-Out	Earliest Ice-Out	Latest Ice-Out	Years of Data
Bemidji	Beltrami	April 26	April 11, 1945,'73	May 22, 1950	71
Itasca	Clearwater	April 23	April 9, 1945,'81	May 18, 1950	68
Kabetogama	St. Louis	April 28	April 13, 1998	May 18, 1996	20
Lk. of the Woods	L.O.W.	April 29	April 8, 2000	May 16, 1996	19
Leech	Cass	April 27	April 9, 1945	May 23, 1950	72
Pokegama	Itasca	April 24	April 6, 2000	May 10, 1996	32
McKinney	Itasca	April 19	March 31, 2000	May 6, 1996	38
Rainy	Kooch.	May 3	April 13, 1998	May 22, 1950	78
Winnibigoshish	Cass/Itas.	April 24	April 6, 2000	May 10, 1996	10

Northeast

Lake Name	County	Average Ice-Out	Earliest Ice-Out	Latest Ice-Out	Years of Data
Fall	Lake	April 27	April 10, 1945	May 19, 1950	58
Gunflint	Cook	May 7	April 15, 1976	May 26, 1966	33
Island	St. Louis	April 25	April 5, 2000	May 8, 1996	23
Lax	Lake	April 28	April 5, 2000	May 13, 1996	34
Mitawan	Lake	May 1	April 19, 2006	May 17, 1996	14
Saganaga	Cook	May 3	April 14, 1998	May 16, 1996	37
Shagawa	St. Louis	April 27	April 14, 1998	May 16, 1996	43
Vermilion	St. Louis	April 29	April 10, 1945	May 23, 1950	89

West Central

Lake Name	County	Average Ice-Out	Earliest Ice-Out	Latest Ice-Out	Years of Data
Artichoke	Big Stone	April 7	March 15, 2000	April 22, 2001	16
Big Stone	Big Stone	April 9	March 22, 1987,'00	April 26, 1951,'75	52
Le Homme Dieu	Douglas	April 20	April 1, 1981	May 1, 1965	11
Minnewaska	Pope	April 13	March 23, 2000	May 7, 1950	98
Osakis	Todd	April 16	March 13, 1878	May 14, 1950	139
Otter Tail	Otter Tail	April 15	April 3, 2000	April 28, 1996	18
Traverse	Traverse	April 9	March 31, 1999	April 22, 2000	12
West Battle	Ottertail	April 16	March 31, 2000	May 5, 1996	19

Central

Lake Name	County	Average Ice-Out	Earliest Ice-Out	Latest Ice-Out	Years of Data
Diamond	Kandiyohi	April 13	March 17, 1987	May 5, 1950	63
Fish Trap	Morrison	April 15	March 26, 2000	April 30, 1996	13
Green	Kandiyohi	April 16	March 22, 1987	May 7, 1951	76
Gull	Crow Wing	April 21	April 2, 2000	May 18, 1950	48
North Long	Crow Wing	April 20	April 8, 1987	May 3, 1979	31
Ox	Crow Wing	April 23	April 9, 1973	May 5, 1975	22

East Central

Lake Name	County	Average Ice-Out	Earliest Ice-Out	Latest Ice-Out	Years of Data
Big Sandy	Aitkin	April 20	March 31, 2000	May 4, 1996	51
Bone	Washington	April 11	March 15, 2000	April 29, 1965	59
Forest	Washington	April 7	March 18, 2000	April 23, 1996	19
Knife	Kanabec	April 12	March 27, 2000	April 23, 1995	16
Prior (Lower)	Scott	April 7	March 14, 1987	April 26, 1975	28
Medicine	Hennepin	April 9	March 8, 2000	May 1, 1965	64
Mille Lacs	Mille Lacs	April 24	April 2, 2000	May 7, 1965	51
Minnetonka	Hennepin	April 13	March 11, 1878	May 8, 1856	131
Rush	Chsago	April 11	March 25, 2000	April 24, 1996	14
Waconia	Carver	April 12	March 15, 2000	May 1, 1941	57
White Bear	Ramsey	April 12	March 21, 2000	May 4, 1950	80

Southwest

Lake Name	County	Average Ice-Out	Earliest Ice-Out	Latest Ice-Out	Years of Data
Sarah	Murray	March 30	March 6, 2000	April 16, 2001	11
Shetek	Murray	April 5	March 8, 2000	April 24, 1962	41

South Central

Lake Name	County	Average Ice-Out	Earliest Ice-Out	Latest Ice-Out	Years of Data
Budd	Martin	March 29	March 6, 2000	April 15, 1993	18
Clear	Waseca	April 2	March 7, 1931,'00	April 27, 1951	96
Lemay	Rice	April 4	March 7, 1987	April 26, 1975	21
Sakatah	Le Seuer	March 29	March 11, 2000	April 17, 2008	11
Shields	Rice	April 4	March 7, 1931	April 27, 1951	105
Sisseton	Martin	April 3	March 13, 1990	April 26, 1951	50
Swan	Nicollet	April 2	March 19, 2003	April 26, 1997	17
Tetonka	LeSueur	April 4	March 14, 1987	April 26, 1975	35

Southeast

Lake Name	County	Average Ice-Out	Earliest Ice-Out	Latest Ice-Out	Years of Data
Pepin	Goodhue/Wabasha	April 9	February 29, 2000	May 20, 1843	83

One of the longer term lake ice-out data sets available for the Midwest comes from Lake Monona and Lake Mendota in Madison, Wisconsin. The record begins for Monona in 1851.