Of all the months in the year, March is one of the most extreme, variable and undependable in Minnesota.

It sometimes sets the tone for the spring season, bringing above-normal warmth and more rain than snow. Or, it can bring winter-like temperatures and heavy snowfalls. The range of temperature is the largest of any month, from 88 degrees F at Montevideo in 1910 and at Winona in 2007, to -50 degrees F at Pokegama Dam in 1897.

It is the month when fishing houses are removed from frozen lakes, frogs begin croaking from thawing ponds, American robins return to backyard feeders, snow cover melts away, soils begin to thaw, puffy clouds appear more frequently in the sky, and the mudroom on the farm is used very frequently.

A snow-free landscape with warm temperatures can lead to early field-working opportunities for farmers and even early planting — as it did in 1878, 1910, 1981 and 2012. In fact, four of the warmest five months of March in state history have occurred since 2000, and the trend in March temperatures is as strongly upward as any month of the year. March of 2012 and 2016 brought the earliest ice-out dates in history for many area lakes.

Form of precipitation changes
Another feature change in the month of March is a change in the character of precipitation. In days of old, March was the snowiest month of the year for most counties in Minnesota. However, since the 1980s, that has changed. Not because precipitation has become smaller in measurable quantity, but because a larger fraction of it is falling as rain rather than snow. March is now the second- or third-snowiest month of the year for most locations in Minnesota, based on historical average monthly totals.

The rainfall that does occur in March has both a beneficial and a detrimental effect, depending on other circumstances. When the soils have thawed, rainfall in March helps to recharge the soil profile, adding to the moisture available for crops to grow. In some cases, this can amount to an extra 2 to 3 inches of soil moisture recharge, especially in the deeper soils of southern Minnesota. However when the soils are still frozen, March rainfall has to run off, enhancing the threat of flooding on the state’s rivers. Sometimes excessively wet conditions during March have contributed to widespread flooding that has delayed the start of the cropping season, as it did in 1965, 1977, 1997 and 2009.

Because March is so erratic in its climate behavior, it is difficult to predict weather patterns for the month. This year, the NOAA climate outlook models for March temperatures are very uncertain. It could go either way, warmer or colder than normal. However, the climate models for March precipitation almost uniformly estimate that the month will be wetter than normal. Such a scenario will likely dampen any thoughts of early field-working opportunities for the 2017 cropping season — at least until the month of April.

Seeley is an Extension climatologist with the University of Minnesota.