Winter is shrinking in its longevity in Minnesota, and its coldest temperatures are not so cold as they used to be.

We have a variety of climate measurements that show these trends. One of the months being affected is November. November is both less cold than it used to be and less snowy as well. An examination of some Minnesota climate statistics shows this to be the case.

I examined the climate histories of three locations in the state that represent landscapes where agriculture is the prevalent player in the local economy: Morris in Stevens County, Willmar in Kandiyohi County, and Grand Meadow in Mower County. In all three cases, I found changes in the climate statistics for November with respect to temperature and snowfall.

Morris, Willmar and Grand Meadow have all seen average low temperature values in November increase over historical normal by about 0.5 degrees F since 1991. This is a relatively small amount of warming for the month as a whole, but the shift in the frequency of low temperatures which fall below 0 degrees F is more pronounced. At Morris, the historical frequency of subzero temperature readings in November was twice per year up until 1990. Since that time it has dropped to once per year.

At Willmar, a similar comparison shows that prior to 1990, subzero temperature readings in November would occur about twice per year. However, since 1991, these readings have diminished to about once every two years.

At Grand Meadow in southeastern Minnesota, where it is generally warmer, there used to be subzero temperature readings in November about once per year, but since 1991 it has occurred only about once every three years.

With respect to November snowfall, all three locations show an average decline, but with an increase in rainfall events during the month. Average November snowfall at Morris has diminished from 6.5 inches prior to1990 to 5.3 inches. At Willmar, the numbers have dropped from 6.7 inches to 6.3 inches. At Grand Meadow, they have dropped from 4.8 inches to 2.8 inches.

The slight drop in average November snowfall since 1990 at Willmar is partially explained by the record-setting November 2001, when November total snowfall measured 32.2 inches.

Less than 1 inch of snow happening more often 

Perhaps a more significant statistic is to examine the frequency with which November brings less than 1 inch of snowfall to these Minnesota communities. Historically, this frequency has been about once every seven or eight years. But since 2000, all of these communities have reported less than 1 inch of November snowfall in one year out of every three, a remarkable change in frequency.

So what does this mean, you might ask? Well, with respect to agriculture, snowfall is generally an asset. It helps insulate the soil from freezing too deeply in the winter season, and when it melts it brings additional soil moisture recharge. As for this month, the National Weather Service outlook for the month of November does not favor warmer-than-normal temperatures for the first time in many years. So we may be in store for a bit more snow.

Mark Seeley is an Extension climatologist with the University of Minnesota.