Minnesota Lake Ice In Dates and Freeze Over Records

Q: How do I know whether the ice is safe?

Contact your state agency and look at the water yourself. Every figure here is the day a lake closed over in a past winter. Ice strength varies across a single lake on a single day with depth, current, springs and snow cover, and a lake that has just closed over is at its most deceptive: it looks like a solid surface and it is a few days of new ice.

Q: Who publishes this winter's Minnesota ice in dates?

Minnesota DNR ice in reports. The DNR asks the public to report ice-in on their own lake and maps the reports as they arrive each autumn, which makes Minnesota the only state with a live statewide picture of the freeze. Their medians are computed from 1950 onward for lake-to-lake consistency, so they will not always match the whole-record figures on this page.

Q: Is ice in getting later in Minnesota?

In this data, yes on 2 of the 2 Minnesota records long enough to state a century trend. The largest is Detroit. Those figures are least squares lines fitted to the observations, the same simple description the ice phenology literature uses. They describe what the record did. They are not projections, and any single lake can swing three or four weeks between consecutive winters.

Q: Have these Minnesota lakes ever failed to freeze?

Not once in the shipped record. All 4 Minnesota water bodies here closed over in every winter their observers logged, which is unusual in this dataset and worth noticing: the water bodies that most often fail to freeze are the deep ones and the Great Lakes bays, and Minnesota's records are neither.

Q: How does ice in compare with ice out on the same Minnesota lakes?

They are the two ends of one season and they have moved in opposite directions. Minnesota lakes appear in both halves of this dataset, and where a lake carries a long enough record on both, the freeze has been arriving later while the thaw has been arriving earlier. The ice-out page for Minnesota carries the thaw half of the same records, lake by lake, from the same source.

Typical ice in on Detroit

November 22

That is the median across 106 recorded winters from 1899 to 2018, the deepest freeze record in Minnesota. Across the 4 Minnesota water bodies on this page the typical closing runs from November 22 on Detroit to December 2 on Waconia. Each of those is a median from a record of past winters, not a forecast or an observation of any lake now.

November 25

Detroit across its last 30 recorded winters

10 days

Between the earliest and latest typical freeze in the state

2 of 2

Records long enough to state a century trend that show a later freeze

0

Winters with no freeze at all, on 0 of these water bodies

Every Minnesota water body, in the order they close

Each bar runs from that water body's earliest recorded closing to its latest, across the whole Minnesota record. The solid dot is the median over every recorded winter and the ring is the median over the most recent 30. The scale starts near the earliest date in the set rather than at January 1, because these are dates a few weeks apart.

Where this winter’s dates come from

The DNR asks the public to report ice-in on their own lake and maps the reports as they arrive each autumn, which makes Minnesota the only state with a live statewide picture of the freeze. Their medians are computed from 1950 onward for lake-to-lake consistency, so they will not always match the whole-record figures on this page.

Minnesota DNR ice in reports

Today against the record

How this point in the season has usually played out

Where today sits in the Detroit record

Today is earlier in the ice season than any closing in this record. The earliest Detroit ever closed over in 106 recorded winters was October 25, in 1919, which is 6 days from now on this year’s calendar.

The median across the whole record is November 22, which is 34 days from now on this year’s calendar. The record itself ends in 2018, so this is a comparison against past winters and not a statement about the current one.

This counts recorded winters, not this one; the current winter comes from the agency linked above.

Detroit, recorded closings by winter

1971 to 2018, 40 winters, median Nov 22

Taller means later in the season. The darker columns are the more recent half of the window. The dashed line is the median across the whole record, not just this window, and the vertical scale starts near the earliest date on the chart rather than at January 1 so that a three week shift stays visible. The source ships the most recent 40 observations here, so this window is the tail of a record that begins in 1899.

Water body by water body

The deepest Minnesota freeze records

Ordered by how much record is behind them. The median is across every recorded winter; the second figure is across the most recent 30, which is the fairer thing to compare against a lake you know today.

Names are reproduced exactly as the source database records them, which is often a shortened form: a lake filed as “Detroit” or “Otsego” is Detroit Lake or Otsego Lake to everyone who lives on it. The names stay as recorded, because United States lakes split unpredictably between “Lake X” and “X Lake”; the subtitle on each card carries the water body type and the state.

Detroit

Lake in Minnesota · 106 recorded winters, 1899 to 2018

Nov 22

typical ice in

Nov 25

last 30 recorded winters

Oct 25

earliest, 1919

Dec 16

latest, 1999

Across the whole record the closing date has moved 11 days later per century across the record.

Its ice out has moved barely at all across the record, so adding the two lines together this lake’s ice season is about 12 days shorter per century.

Mean closing date per decade. Only decades with four or more observations appear, and the scale starts near the shortest bar rather than at January 1 so that small differences stay visible rather than collapsing into one length.

Green

Lake in Minnesota · 66 recorded winters, 1908 to 2014

Dec 2

typical ice in

Dec 2

last 30 recorded winters

Nov 18

earliest, 1932

Dec 23

latest, 1998

Across the whole record the closing date has moved 3 days later per century across the record.

Its ice out has moved 9 days earlier per century across the record, so adding the two lines together this lake’s ice season is about 12 days shorter per century.

Mean closing date per decade. Only decades with four or more observations appear, and the scale starts near the shortest bar rather than at January 1 so that small differences stay visible rather than collapsing into one length.

Waconia

Lake in Minnesota · 50 recorded winters, 1940 to 2016

Dec 2

typical ice in

Nov 30

last 30 recorded winters

Nov 16

earliest, 1976

Dec 19

latest, 2015

The record spans 76 years, under the 80 year span needed to state a century trend. The median and the extremes above are unaffected.

Mean closing date per decade. Only decades with four or more observations appear, and the scale starts near the shortest bar rather than at January 1 so that small differences stay visible rather than collapsing into one length.

Pepin

Lake in Minnesota · 43 recorded winters, 1860 to 1905record ends 1905

Nov 27

typical ice in

Nov 26

last 30 recorded winters

Nov 2

earliest, 1882

Dec 30

latest, 1890

The record spans 45 years, under the 80 year span needed to state a century trend. The median and the extremes above are unaffected.

Mean closing date per decade. Only decades with four or more observations appear, and the scale starts near the shortest bar rather than at January 1 so that small differences stay visible rather than collapsing into one length.

A wall of shelf ice rising above a lake surface strewn with broken plates of new ice and patches of dark open water, under a blue sky with high cloud — Shelf ice standing above a field of broken new plates, with open water still showing between them. This is the state a lake is in for days or weeks before anybody writes a closing date against it, and it is why two observers standing on the same shore can pick two different days. “Ice along Lake Superior” — National Park Service, Pictured Rocks National Lakeshore — Public domain

Every record

All 4 Minnesota water bodies with a freeze record

Water body	Record	Typical ice in	Last 30 winters	Earliest	Latest	Change per century
Detroit	1899 to 2018 (106)	Nov 22	Nov 25	Oct 25 1919	Dec 16 1999	+10.6 days
Pepin	1860 to 1905 (43)	Nov 27	Nov 26	Nov 2 1882	Dec 30 1890	record too short
Green	1908 to 2014 (66)	Dec 2	Dec 2	Nov 18 1932	Dec 23 1998	+3.4 days
Waconia	1940 to 2016 (50)	Dec 2	Nov 30	Nov 16 1976	Dec 19 2015	record too short

Dates are day of year, rendered on a common non leap calendar so the same stored value always reads the same way. Freeze dates are stored on a winter axis, where a January closing sorts after a December one instead of jumping back to the start of the year; the labels above are ordinary calendar dates. “Change per century” is a least squares line through the observations, shown only where a record spans 80 years or more, because a century figure extrapolated from a 40 year window describes the decades that happened to be sampled rather than the lake. “Winters open” counts the winters the source marks as never closing over, which are observations rather than gaps and are not included in the record counts.

Both ends of the season

How much shorter the Minnesota ice season has got

2 Minnesota water bodies carry a least squares slope on both the freeze and the thaw, which is the only way to see the season from both ends at once. Adding one lake’s own freeze line to its own thaw line, the widest here is Green at 11.9 days shorter per century.

That is addition on two numbers the source data already publishes for that lake: a description of what one lake’s own record did across the years somebody was watching it, not a model and not a projection of what the next decade will do.

Freeze arriving later
Thaw arriving earlier

Each bar is one Minnesota lake's own freeze line added to its own thaw line, both fitted by least squares to that lake's observations and both already published in the source data. Only records spanning 80 years or more on both variables appear, which is why not every water body in the table above is here.

Reading the record

What the Minnesota freeze record shows

Of the 2 Minnesota freeze records long enough to state a century trend, 2 show the closing date arriving later. Those are least squares lines fitted to observations, the same simple description the ice phenology literature uses. They describe what each record did. Any single lake can swing three or four weeks between consecutive winters, and several here have.

A typical ice in date is a median drawn from a record: the middle of a distribution whose ends, on these Minnesota records, sit 33 days apart on Waconia alone. It describes past winters, not the current one.

Minnesota DNR defines ice-in as the whole lake being frozen over with the cover holding through the winter, which is a stricter test than the first-freeze definition several other series in this dataset use. A lake that skins over in a cold week and opens again in a thaw has not had its ice-in date under that rule.

The state that counts both ends. Minnesota has more reporting lakes than anywhere else in the country because the DNR asks ordinary people to send the date in, and it is the only state that runs the same exercise in November as it does in April. In a cold autumn the reports sweep south from the Arrowhead over about three weeks, which is the reverse of the way ice-out moves.

A record that ends in 1905. Lake Pepin, the wide reach of the Mississippi below Red Wing, has 43 recorded closings between 1860 and 1905 and nothing after. It is a river lake with current running through it, which is exactly why somebody was writing the date down, and exactly why it froze later than its latitude suggests.

Satellite view of Lake Superior in mid December with the surrounding land under snow, the open lake dark, and pale new ice showing in the shallow western bays — Lake Superior on December 15, with the first ice of that winter forming in the shallow western bays while the deep middle stays open. Depth is what sets a freeze date: a shallow bay gives up its summer heat in weeks and the deep middle can take all winter or never manage it. “Lake Superior (MODIS 2018-12-20)” — MODIS Land Rapid Response Team, NASA GSFC — Public domain

Provenance

Where these Minnesota numbers came from

The observations

265 recorded closings across 4 Minnesota water bodies, from 1860 to 2018. Only records with 40 or more usable observations are included, and every derived figure is computed from them.

Benson, B., Magnuson, J. and Sharma, S. (2000). Global Lake and River Ice Phenology Database. (G01377, Version 1). Boulder, Colorado USA. National Snow and Ice Data Center. https://doi.org/10.7265/N5W66HP8 Accessed 2026-08-24.

Detroit Lake has the earliest typical freeze of any century long record here, and its own record runs from 1899 to 2018 with no winter in which it failed to close.

Common questions

Minnesota lake ice in FAQ

When do lakes usually freeze over in Minnesota?

It depends on the lake, so this page gives a figure for each one instead of a single state number. Detroit has the deepest record in Minnesota at 106 recorded winters and typically closed over around November 22, or November 25 across its most recent 30 recorded winters. Across the 4 Minnesota water bodies here the typical date runs from November 22 on Detroit to December 2 on Waconia. Every one of those is a median drawn from past winters and none of them describes this one.

How do I know whether the ice is safe?

Who publishes this winter's Minnesota ice in dates?

What exactly counts as ice in on a Minnesota lake?

Minnesota DNR defines ice-in as the whole lake being frozen over with the cover holding through the winter, which is a stricter test than the first-freeze definition several other series in this dataset use. A lake that skins over in a cold week and opens again in a thaw has not had its ice-in date under that rule. That matters most when you compare two lakes against each other and least when you compare one lake against its own past, which is what every figure on this page is built for.

How far back do Minnesota freeze records go?

The oldest freeze observation in Minnesota in this dataset is from 1860 and the most recent is from 2018. Across the state this page covers 4 water bodies with at least 40 recorded winters each, 2 of which span a century or more, and 265 individual freeze dates in total. Almost none of it was collected for science. It was kept by field stations, fisheries staff, harbour masters, newspapers and individuals for practical reasons, and became a climate record afterwards.

Is ice in getting later in Minnesota?

Have these Minnesota lakes ever failed to freeze?

How does ice in compare with ice out on the same Minnesota lakes?

A frozen lake under flat grey winter light with dry reed beds along the near shore, bare branches at the left edge and a low wooded shoreline in the distance — A closed Minnesota lake under flat January light. This is the state that asks the public to report exactly this, one lake at a time, and maps the reports as they arrive: the only statewide ice in picture anybody publishes. “Frozen Lake Elmo Minnesota (24820237837)” by Tony Webster from Minneapolis, Minnesota, United States, CC BY 2.0

The other end of the season

Ice in, ice out, and the rest of the Minnesota winter

Minnesota ice inWhen 4 Minnesota water bodies have typically closed over, from 265 recorded winters. You are on it.

Minnesota ice outThe spring half of the same records, lake by lake, from the same source. Together they are the length of the Minnesota ice season.

Every state with a freeze recordThe national picture, the ice season closing from both ends, and every state with a freeze record.Minnesota winter outlookWhat NOAA expects from the season that puts the ice on in the first place.Minnesota first snowThe other autumn threshold, on the same calendar and from a different federal record.

More Midwest states with a lake freeze record

Ice in dates are historical observations compiled by the National Snow and Ice Data Center. They describe past winters only: a median freeze date is a record of winters that have already happened, and says nothing about the ice on any lake today. For current ice and for anything involving going out on it, contact Minnesota DNR ice safety. National picture: every state with a lake freeze record → The thaw half: Minnesota lake ice out dates.
Hero image: “Frozen Lake Elmo Minnesota (24820237837)” by Tony Webster from Minneapolis, Minnesota, United States, CC BY 2.0