Note: this story was initially about the record-holding winter of 1877-78. In light of extreme winter warmth during the 2023-24 winter, it has been re-worded to account for changes in its standing, with more edits likely through the spring of 2024.
For over 145 years, the meteorological winter of 1877-78 (December through February) has stood as the warmest on record in the Twin Cities, with December of 1877 so outrageously warm that its records had seemed untouchable. December 2023, however, surpassed December of1877 by 0.5 degrees F in the Twin Cities, and the 2023-2024 winter maintains a sizable lead over 1877-78 as of February 20, 2024 and appears set to become the new #1 for this dubious honor.
The 1877-78 is understood by climate scientists to have been the result of a potentially very intense El Niño, on par with the strongest documented during the in the past 75 years and likely stronger than even the major El Niño of 2023-24.
Dubbed "the Year without a Winter," December-February of 1877-78 had an average temperature of 29 degrees F in the Twin Cities. Until 2023-24, a healthy margin of 2.1 degrees separated it from the next-warmest winter on record, 1930-31, which had an average temperature of 26.9 degrees. Closely following in 3rd place (now 4th) is the winter of 2001-02, at 26.8 degrees F.
The 1877-78 winter had defended its longstanding title almost effortlessly, even as winters across the entire region warmed rapidly after 1970, in response to global temperature increases, and as the Twin Cities area has has grown warmer from urban expansion.
Although the warmth of the Year Without a Winter could be detected into April, the the most outstandingly warm month was December. In the Twin Cities, the margin between the now #2 warmest December 1877 and #3 (1913) is 3.3 degrees, which is larger than the temperature range separating #3 on the list from #17.
Duluth's observations in the late 1870s (and through the 19th century) were taken near the Lake Superior shore, which produces a substantial winter warming effect, making for difficult comparisons with modern records, now taken well "up the hill," at the airport. As a result, December of 1877 had remained an astonishing 5.8 degrees warmer than any other December on record, until December of 2023 moved into the #2 spot, and cutting the margin down to 2.6 degrees F. We do not know how warm December 2023 or the winter of 2023-24 would have been at the old site near the lake, or what the temperature of 1877-78 would have been near today's airport.
The warm winter of 1877-78 brought major hardships to a population dependent on travel by horse and sleigh. Most roads at the time were made from dirt, so the warm conditions, the lack of snow, and the occasional rains made a muddy mess of transportation routes, with businesses, families, and individuals bogged down in the impassable mud.
Farmers near Minneapolis were plowing fields until late December 1877. But in spite of the general warmth, three days with subzero temperatures in early January 1878 froze the Mississippi River in Saint Paul so that it was closed for navigation until the 28th of February. After January 7 only three days through the remainder of the 'cool' season would experience single digit temperatures or lower.
The "Monthly Weather Review" from February 1878 reported prairie fires in Minnesota, Dakota, and Kansas. In that same month active insects in Iowa, grasses sprouting in Dakota, and the ice cover in Duluth harbor broken up by heavy winds were all reported.
The continuing warmth of March 1878 allowed the first boat arrival in Duluth on the 17th. From research done by naturalist Jim Gilbert, Lake Minnetonka ice is known to have gone out at the earliest date on record, March 11, some 33 days earlier than its average ice-out date of April 13. Lake Osakis lost its ice on March 13th, the earliest in 142 years of records.
The winter of 1877-78 while warmest of record at Minneapolis-St. Paul, was not a dry winter. The months of December 1877 through February 1878 saw 3.09 inches of precipitation. For comparison, the 1991-2020 normal for December through February is 2.93 inches.
Below are excerpts from the Minneapolis Tribune, courtesy of long time climatology volunteer, Tom St. Martin.
Minneapolis observer William Cheney regularly prepared monthly newspaper weather summaries which, to the extent that they were published, augment and sometimes clarify data contained in his meteorological registers as submitted to the U.S. Weather Bureau/ U.S. Army Signal Corps. The following comments are taken from the observer?s reports as published in various 1877-1878 editions of the Minneapolis Tribune:
- November 1877: Warmest November since 1870. Rain on the 1st and 2nd with snow on the 7th and 8th falling to a depth of three inches. Two inches of snow on the 18th. Three inches of snow on the 27th and 28th accompanied by a high wind. Snow on the 8th and 18th melted soon after it fell. Rain on the 21st made the roads bad. Large proportion of cloudy weather.
- December 1877: Unprecedented, untimely, unpleasant and sub-boreal weather. Large number of foggy and rainy days. Deep mud. Farmers plowing as late as the 23rd. River free of ice above and below Lake Pepin up to the last day of the month. Flowers blooming on the 28th. Five inches of snow on the 4th and 5th gave a short period of good sleighing. Rain fell more or less every day from the 17th to the 27th, inclusive. Heavy fog on 18, 19, 20, 21. Sleighing entirely gone by mid month with roads almost impassible because of mud. Only four entirely clear days and fifteen cloudy days. Closest approach to December 1877 was December 1857.
- January 1878: The month was colder than December but unusually warm for January...there were only two very cold days during the month...no snow fell in sufficient amounts for sleighing until the 30th when about six and one half inches of light snow gave pretty good sleighing in the city but not sufficient for heavy teaming. The mud of December frozen by the cold of the first few days of January made the roads exceedingly rough and travel thereon very uncomfortable. The absence of snow proved a serious drawback to business of all kinds...thirteen cloudy days...
- February 1878: This month closes the most remarkable winter ever known in Minnesota. Scarcely any sleighing, muddy roads, some fog, only five days...below zero,...and a mean temperature ten degrees warmer than any winter of which I have any record...The almost entire absence of snow has been somewhat detrimental to business generally and has proved a serious drawback to logging...The winter certainly has been a pleasant and comfortable one, making small demands on the fuel pile...While the mean temperature of the month was about the same as February of last year, it was in some respects less pleasant. There was more cloudy weather and two storms gave us five and one fourth inches of snow, making considerable mud...The season is not quite so far advanced as last year though wheat sowing is reported to have begun in some parts of the state...thirteen cloudy days....
- March 1878: This was decidedly the warmest March of which I have any record...being 21 degrees warmer than the average of March for the last thirteen years and twelve degrees warmer than the average of 33 years at Ft. Snelling. There were occasional showers throughout the month, which, together with the mild temperatures, served to bring forward vegetation very rapidly...Wheat sowing was nearly all completed before the close of the month....No snow fell except for a slight sprinkling on the morning of the 30th, no enough to whiten the ground...six cloudy days....
- April 1878: This month, like its immediate predecessors, was an exceptional one, being the warmest April of which I have any record....Only once during the month...did the thermometer fall below freezing...The rainfall was fully up to average...so that vegetation made steady and rapid progress...nine cloudy days...
- May 1878: While the winter months and the first two months of spring were exceptionally warm, the month of May was unusually cold, being the coldest May since 1867....no serious frosts have occurred, however, and with the abundance of rain, the weather has, on the whole, been very favorable to crops...The rain was...well distributed throughout the month, although the larger part fell in the latter half....a slight sprinkling of snow on one day...."