Right on time north of the Iron Range and a little early elsewhere, widespread frost hit much of the region away from Lake Superior on Friday and was expected again this morning.
The National Weather Service in Duluth on Friday issued a freeze warning for Northeastern Minnesota north of U.S. Highway 2, including all of Itasca and Koochiching Counties and most of St. Louis, Lake and Cook counties away from Lake Superior, to be in effect from 3 a.m. to 8 a.m. today.
If skies cleared and winds diminished overnight, temperatures may have dropped to 28 degrees or lower in those areas, considered a hard freeze and the official end of the growing season.
Near Lake Superior, in the Twin Ports and across northern Wisconsin, a frost advisory was posted, with temperatures expected to drop to between 29 and 33 degrees. At those temperatures, frost can damage plants but many can survive.
“It should stay warm enough near the lake to prevent a freeze, but we could still see frost in low-lying areas near the lake,” said Mike Stewart, meteorologist in charge of the Duluth National Weather Service office. “For some areas, this is going to be it” for the growing season.
The cold snap will be short-lived, with highs back in the 60s by Sunday and for most of next week, and lows in the upper 40s.
The frost is not far from normal for many areas, although a hard freeze would be ahead of schedule.
Cook has Minnesota’s earliest average first frost date, on Sept. 10, with an average hard freeze by Oct. 2. Hibbing averages a first frost by Sept. 14. International Falls averages its first frost on Sept. 17, according to the Minnesota State Climatology Office, with Ely on Sept. 24.
The Duluth airport on average sees a frost by Sept. 23 and a hard freeze by Oct 18. Duluth’s harbor doesn’t see a first frost on average until Oct. 18 and escapes a hard freeze on average until Nov. 2.
Friday morning lows
PINE RIVER 26
SILVER BAY 27
CHISHOLM-HIBBING AIRPORT 28
BIGFORK 29
COTTON 29
CRANE LAKE 30
GRAND RAPIDS 30
MAKINEN 30
HILL CITY 31
WALKER 31
TWIG 31
NAMEKAGON, Wis. 31
EMBARRASS 31
CASS LAKE 31
BRULE 31
HERMANTOWN 31
AURORA 31
EVELETH-VIRGINIA AIRPORT 32
COOK 32
KABETOGAMA 33
HAYWARD AIRPORT 33
BRAINERD AIRPORT 33
DULUTH Weather Service 33
INTERNATIONAL FALLS 34
ELY 34
SUPERIOR 35
Source: National Weather Service
