Temperature departures compared to normal at 2 p.m. Monday, 3/19 (Penn State)

The warmth underway in Chicago borders on the unreal. Between Wednesday and Sunday, it set new record highs five days in a row, all 80 or higher. Four of Chicago’s five warmest March days on record all occurred in this stretch. Before this year back to 1871, the most 80 degrees days it could string together in March was two and there had been only 10 80+ degree days total (in the month).

If Chicago manages to hit 79 today, it will have set a record high on six consecutive days for only the second time on record

Some of the most impressive heat relative to normal has occurred in International Falls, the so-called “icebox of the nation”. Between Friday and Sunday, it smashed record highs by at least 10 degrees. On Saturday, it demolished its record of 55 (from 1968) by 22 degrees, hitting 77. Incredibly, in 9 of the last 10 days, it has tied or broken a record high, including today. Records in International Falls date back to 1895.

Unrivaled March warmth has also descended on the Twin Cities. It has set new record highs in 8 of the last 10 days (including today, when it has risen to 75, at least). The high of 80 degrees on March 17th was the earliest 80 degree temperature on record (dating back to the 1870s). The average high there right now is 42. Minneapolis Star Tribune meteorologist Paul Douglas says the warmth is mind-boggling.

“In 32 years tracking weather I’ve never seen anything quite like this, certainly not in March,” he blogged. “We’ve always had our atmospheric ups and downs, but this is OFF THE SCALE WEIRD; even for Minnesota.”

Andrew Freedman at Climate Central describes the record warmth in Madison, WI Saturday, stating: “the temperature only got down to 60°F ... an all-time March record-high minimum temperature. The average temperature in Madison that day was 70°F, which is the warmest average temperature of any March day on record there.”

Wunderground’s Jeff Masters notes Winner, South Dakota soared to a scorching 94 Sunday, the earliest 90+ reading on record in the Northern Plains.

And it’s not just the heat. In Rochester, Minnesota, the dew point - a measure of humidity - climbed to 62 degrees - breaking its March record of 56 by 6 degrees (records there date back to 1948).

While the core of the heat has affected the Upper Midwest, the warmth has spilled over to the Northeast at times. Boston hit a record of 74 Sunday and has at least tied a record of 72 today. Scores of record highs have already been set so far today in the eastern half of the U.S. Here’s a small selection:

Traverse City, Green Bay, Rhinelander, Duluth, Mt. Washington, Niagara Falls, Fargo, Augusta (ME), Burlington, Concord, Ithaca, Detroit, Louisville, Indianapolis, Eau Claire, Cleveland, Wilkes-Barre Scranton, Cincinnati, Buffalo...

As we discussed last Thursday, the cause of the heat wave is a huge stationary ridge of high pressure sprawled out over the eastern half of the U.S. which has moved little in the past week. It is forecast to slowly break down this week, but, even as it does, temperatures will remain well above average into the weekend.

Related: Greenhouse gases and global warming activate the steroid era of our atmosphere

Back door cold fronts kick heat out of mid-Atlantic, Great Lakes (from Friday)