The Lost Winter of 2023-24

Where on Earth did Minnesota's winter go? The State Climatology Office  looked for proof of this iconic season's existence from early December 2023 through early April 2024, but was only able to find some traces of it that were left on the ground during mid-January, before melting away during yet another heatwave. A brief resurgence in mid- February brought snow and hope to southern Minnesota, but vanished within days, and a late-month flourish lasted 36 hours before being chased away by yet another warm spell. A legitimate winter storm at the end of March doubled some seasonal snowfall totals, but came too late to erase the memories of bare ground and chirping birds through the heart of winter.

The winter season can be defined meteorologically (December through February), astronomically (December 21 to March 21), or based on when we actually experience winter-like conditions, meaning cold and snow. By that latter definition, a typical winter lasts from November into March or even April, but this year, most of Minnesota had only a total of about 2-3 weeks of it, and some of that was around Halloween!

Instead, the winter was dominated by warmth and snowlessness, with the December-through-February meteorological winter becoming the the warmest on record at almost all stations. Winter heatwaves in December, January, and February produced record high temperatures, record high minimum temperatures, all-time monthly high temperatures, and some "firsts" for winter warmth too. International Falls recorded its first January 50 F temperature in its history, and the Twin Cities broke its record for number of 50 F days for the season by early February, racking up 18 by the end of the month. St. Cloud and the Twin Cities both observed their longest January Thaw on record. Rochester and the Twin Cities both observed their warmest February day in recorded history.

Most areas in the state had received less than 50% of their normal snowfall through the end of February, and had observed 30-70 days since December 1 with no snow on the ground.

The warm conditions and the lack of snow reinforced each other. Snow cover reflects incoming sunlight, which prevents the ground from heating up and warming the air above it. Snow therefore prevents warming and promotes cooling of the local air mass, with stronger effects as the snow deepens. Bare ground, on the other hand, allows much more sunlight to reach the earth, which promotes warming of the air.

The differences in air temperature between bare and snow-covered can be significant. Looking at all winters since 1994, Milan in western Minnesota averaged nearly 23 degrees F when there was no measurable snow on the ground, versus 12 degrees F with 10+ inches of snow cover, and about 4.5 degrees F when snow depth was at least 20 inches. The lack of snow in 2023-24 definitely contributed to the many extremes of warmth observed in Minnesota.

The warm conditions during the early winter delayed ice formation on area lakes, with some observing their latest ice-in dates on record (though Minnesota has far fewer lakes with high-quality ice-in records than it has for ice-out dates). When lake ice did form, it was of inconsistent quality, leading to widespread unsafe conditions, even during the middle and end of January. The US Pond Hockey Championships at Lake Nokomis in Minneapolis had to cancel its final weekend, outdoor ice rinks came down early and after little use across the state, and many other major events were shortened, postponed, or altered significantly. Lake ice came off early too, with the earliest ice out on record set at Clear Lake in Waseca County on March 1st, 2024. The previous earliest date was March 6th, and the lake has mostly consistent records into the1870s.  

The following table summarizes temperature statistics for the December through February meteorological winter.

December-through-February 2023-24 seasonal statistics for Minnesota's first-order climate stations. "Normal" refers to 1991-2020 averages. All values preliminary until February is complete.

* In Duluth, the winter of 1877-78 still stands as the warmest on record, with a temperature of 28.1 F. At that time, however, the Duluth station was on Superior Street, within about 1000 feet of Lake Superior. The lake has a large warming effect during winter (and a cooling effect during summer), making some comparisons between the historical and current stations difficult. We do not know what the temperature of 1877-78 would have been near the airport, nor what the temperature of this winter was at the original observing location.

Updated Aug 9, 2024

KAB