Parts of northeastern Minnesota and western Wisconsin were under a late summer frost warning last night. Residents took steps to protect sensitive plants.

The National Weather Service warned that a cold ridge of high pressure settled over the border from Sunday night to Monday morning.

The weather service said that created perfect conditions for a quick drop in the temperature into the mid-30s, and possibly below freezing in spots. The frost warning was set to expire at 7 a.m. today.

In Albert Lea, the air temperature reached 45 degrees at about 4 a.m. this morning.

It comes during an unseasonable cold snap.

The weather service reports the high temperature in the Eau Claire, Wis., on Saturday was 62 degrees — which sets a new record for the lowest high temperature for Aug. 29 for the town.