Weather stations in all 50 states -- even Hawaii -- reported observations of freezing temperatures overnight as wintry cold spreads across North America.
The National Weather Service's Twin Cities forecast office in Minnesota noted the occurrence in a tweet this morning, with a map showing sub-freezing temperatures extending across nearly the entire continental United States.
Wintry weather warnings extend across the Lower 48, from lake effect snow warnings around the Great Lakes to hard freeze warnings across northern Florida and southern Georgia, Alabama and Mississippi, according to the weather service.
Snow cover extends over slightly more than half of the country, compared with 12 percent at this time last year, according to the weather service.
While Hawaii is not being affected by the same cold snap, it did record freezing temperatures overnight atop Mauna Kea, a 13,800 foot dormant volcano on the island of Hawaii.
The overall outlook across the country is frigid and bleak, according to a weather service forecast discussion:
"A deep low pressure system centered over southeastern Canada will continue to push polar air over the eastern half of the US this week. Well below average temperatures will reach the Gulf Coast, with most of the Mid-Atlantic states barely getting above freezing Tuesday and Wednesday. In the Midwest, periods of lake effect snow will continue south and east of the Great Lakes through Wednesday."
But local forecasting website Foot's Forecast was careful to note, it's not exactly accurate to blame this cold snap on the "polar vortex", a swirling column of frigid air that usually stays over the Arctic. The vortex itself remains over northern Canada, though it is still far enough south to push the abnormally cold air over the country, according to a post on Foot's Facebook page.