(This article, first published Monday, was updated Tuesday and Wednesday mornings with the latest records and forecast information.)

The Great Lakes and Northeast are witnessing some of the hottest weather they’ve ever experienced so late in the year.

The abnormal warmth comes at a time residents are normally bundling up in the frosty morning air and all the talk is the changing foliage. Instead, temperatures have shot up to 90 degrees all the way north of the Canadian border. In some areas, like Chicago, 90-degree heat toasted the region for an entire week.

Consider some of the incredible heat milestones set in recent days:

Interestingly, locations in Vermont and Maine were as warm or warmer than areas much farther south early this week. For example, Caribou’s mid-afternoon temperature of 88 degrees on Monday matched the reading in Tallahassee, Fla. Burlington, at 92 degrees, Monday was warmer than Washington, D.C., where the high was 91. Almost all of these locations were hotter than Phoenix, which had an unusual four straight days below 90 degrees.

The hot weather came as the result of unusually strong heat dome, which developed last week over the Upper Midwest and drifted into the interior Northeast early this week.

After one more day of record-challenging heat in the Northeast Wednesday, strong cold front to the northwest will crush this heat dome, ending this summerlike fling.

This latest heat wave is the second of historical significance in this region this calendar year. In February, it witnessed another round of record warmth. Chicago set record highs on four straight days, climbing to around 70 degrees — its most pronounced early season warm spell ever recorded. And Milwaukee and Green Bay both set their all-time highs for February.

Milwaukee has now, in the same year, experienced its warmest weather ever recorded so early and late in the calendar.

The increasing prevalence of such warm weather extremes is exactly what we expect as concentrations of heat-trapping greenhouse gases rise in the atmosphere.