It’s mid-May, a time associated with softball games, senior proms and sometimes even shorts and sandals.

But just a week before Memorial Day, Minnesotans were surprised with a cold, wet forecast that included snow Sunday in northeastern areas and, for most of the state, an advisory for frost through Monday morning that could damage any recently planted annuals.

The frost “definitely is fairly unusual, especially for the second half of May,” said Tyler Hasenstein, a National Weather Service (NWS) meteorologist. “We’re about five degrees from record-setting cold.”

The record low for May 19 at Minneapolis-St. Paul International Airport — a chilly 33 degrees — was set in 1961, he said, while Sunday night’s overnight low will be about 37 or 38 degrees.

Sunday morning, the NWS warned residents on Twitter that the weather “will feel more like March today than mid May with windchill readings in the 30s,” adding that frost was expected in the evening. The NWS declared a frost advisory until 8 a.m. Monday for more than 30 counties around the metro area and in northwestern and southern Minnesota.

Most of Minnesota saw rain and temperatures in the 40s Sunday. Near Duluth, though, more than 2 inches of snow fell.

Hasenstein called snow this late in the season “fairly unusual” but noted that the record for the latest snowfall in northeastern Minnesota was set om May 28, 1965.

As residents in the southern half of the state tallied up rainfall totals Sunday, the NWS reminded people that a flood warning continues at various points along the Minnesota River, including near Jordan, Savage, Morton and Montevideo, affecting four metro-area counties along with Chippewa, Lac qui Parle and Yellow Medicine counties.

The week’s forecast shows the rain will likely persist.

Monday is the “best overall day for doing anything you might have missed doing during the weekend,” Hasenstein said, with temperatures in the 60s and sun expected.

Beginning Tuesday afternoon and extending into Wednesday, the rain will be back in southern Minnesota, with a chance of showers in the metro area. On late Thursday into Friday, rain is also anticipated, Hasenstein said.

As Memorial Day weekend approaches, temperatures will be in line with seasonal averages, with highs in the 70s, Hasenstein said.