A sprawling stretch of Frost Advisories, plus one Freeze Warning, spans five states overnight Monday into Tuesday as the season’s coldest air yet settles over the Upper Midwest and Great Lakes.
Four separate National Weather Service offices issued advisories covering a huge swath of Minnesota, Wisconsin and Michigan’s Upper Peninsula, with lows expected to fall into the low-to-mid 30s across the region.
Minnesota and Wisconsin: The Widest Advisory of the Night
The NWS Duluth office issued its broadest advisory of the event, covering more than a dozen counties from midnight to 8 AM CDT Tuesday.
Temperatures as low as 34 degrees will bring frost to inland areas away from Lake Superior, stretching across Koochiching, North St. Louis, Itasca, Cass, Crow Wing, Aitkin, Carlton, and Pine counties in Minnesota, plus Price, Ashland, Bayfield, Burnett, Douglas, Iron, Sawyer and Washburn counties in Wisconsin.
Cities in the advisory include Duluth, Brainerd, Hibbing, Grand Rapids, International Falls, Ely, Superior and Ashland, among many others.
Michigan’s Western U.P.: A Frost Advisory and a Freeze Warning Together
The NWS Marquette office issued two separate products for the western Upper Peninsula. A Frost Advisory runs from 2 AM to 9 AM EDT Tuesday for Ontonagon, Marquette, Alger, Luce, Gogebic, Dickinson, Delta and Schoolcraft counties, with lows near 33 degrees affecting cities including Marquette, Escanaba, Munising, Ironwood and Iron Mountain.
A stronger Freeze Warning covers Baraga, Iron and Southern Houghton counties over the same overnight window, with temperatures forecast to drop to 30 degrees near Kenton, Iron River, Sidnaw and L’Anse. Unlike a Frost Advisory, a freeze can kill crops outright and damage unprotected outdoor plumbing.
Eastern U.P.: Chippewa and Mackinac Counties
Further east, the NWS Gaylord office posted a Frost Advisory for interior sections of Western and Central Chippewa and Western and Eastern Mackinac counties, running from 8 PM Monday to 9 AM EDT Tuesday with lows as low as 33 degrees.
Northern Wisconsin: Vilas, Oneida and Forest Counties
The NWS Green Bay office rounded out the region’s advisories, covering Lincoln, Oneida, Vilas, Florence and Forest counties from midnight to 7 AM CDT Tuesday. Rhinelander, Eagle River, Tomahawk, Crandon and Merrill are among the communities expecting frost as lows dip to 33 degrees.
What to Do Before the Cold Arrives
Cover or bring in tender plants, potted flowers and late-season garden vegetables before temperatures drop after sunset. Lightweight sheets or frost cloths work best; avoid letting plastic touch the foliage directly, since it can conduct cold and worsen damage.
In the Freeze Warning zone around Baraga, Iron and Southern Houghton counties, residents should also protect outdoor plumbing. Wrap, drain or let exposed pipes drip slowly overnight, and disconnect and drain garden hoses and in-ground sprinkler lines.
Updated forecasts are available at weather.gov for each local office.
