The Northand’s first widespread frost advisory has been issued by the National Weather Service in Duluth with temperatures on Wednesday morning expected to dip down to the mid-30s and maybe lower 30s in some areas.
The advisory means that frost, which can occur even at temperatures just above freezing, is possible and that sensitive outdoor plants might be damaged.
The advisory is posted for all of Northeastern Minnesota as well as Douglas, Washburn and Burnett counties in Northwestern Wisconsin.
The frost is forecast just about right on time for many areas of the Northland. Duluth’s hilltop on average sees its first 32-degree low temperature on Sept. 30, according to data from the National Weather Service, while International Falls and Hayward see theirs Sept. 14, Hibbing on Sept. 15 and Ashland on Sept. 18.
Temperatures near Lake Superior will remain warmer, and the Duluth harbor’s first frost on average doesn’t come until October.
And it’s definitely not an early frost if it happens. Every area of the Northland has seen frost in August in the past, including as early as Aug. 27 in Duluth, in 1986, and Aug. 13 in Hibbing, in 2004.
Some areas of the Northland may have seen a light frost back on Aug. 14, with temperatures dropping into the lower 30s in areas north of Duluth. A few traditionally cold reporting stations like Brimson also saw some frost Friday and Saturday morning.
Duluth on average will see a hard, killing freeze, with temperatures at 28 degrees or colder, starting Oct. 6, according to data from the Minnesota Climatology Office.
The frosty morning temperatures come just a few days after Duluth notched yet another 80-degree day, on Sunday, the 52nd day so far this year with temperatures at 80 or above. That trails only 1988, with 53, for the most 80-degree days on record.
Duluth experienced its warmest meteorological summer on record — June, July and August — this year.