CNN
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Much of the eastern United States will enjoy early fall weather over Labor Day weekend, after tens of millions of people were hit by July heat this week.

A strong cold front is moving through the region this weekend, bringing cooler air from Canada into early next week. This will keep the north-central and northeastern U.S. on a temperature rollercoaster, while the South could get its first notable break from the intense summer heat in weeks.

But summer is morphing into fall as the world warms from fossil fuel pollution, so the cooling is expected to last no more than a few days before temperatures creep back up. The shift from warm to cool to warm is a trend that could continue well into fall, according to the latest seasonal forecasts.

The north-central US will be the first to enjoy relief from the front as it moves into the country Saturday night. Cooler air will spread further south and east on Sunday, and by evening, fall-like weather will have reached most of the Midwest.

Chicago will see a late September-like high of 70 degrees Celsius for Labor Day Monday. It will be a dramatic change from the heat that hit the city earlier this week. On Tuesday, Chicago’s O’Hare International Airport soared to a record-breaking 99 degrees Celsius for the date, marking the highest temperature recorded at the location all summer.

Next week’s cooldown won’t be the first brief bout of autumn the city has experienced this month. Much of the northern U.S. has been on a temperature rollercoaster in the second half of August, going from sweltering summer heat to a taste of fall and back again.

The cold front will move through the Northeast on Monday, but the region will have had a taste of fall before the front. Cooler air first appeared in parts of the Northeast on Thursday after stormy weather moved through on Wednesday.

It felt like mid-September in New York City on Thursday, with mostly cloudy skies and daytime temperatures in the mid-70s. Cooler, cloudier weather with daily showers likely will continue across much of the Northeast through the weekend.

Areas south of the Northeast may have to wait until Tuesday for a few days of heat relief.

Washington, D.C., reached a high of 101 degrees on Wednesday, breaking the daily record and just a few degrees shy of the metropolis’ warmest August reading. Wet weather on Friday could provide some brief heat relief, but the coolness will be short-lived until a cold front moves through the area early next week.

The Southern US has literally been a hot spot all summer, but this week parts of the region have started to see a cooling trend.

Wet, cloudy weather this week brought temperatures along the western Gulf Coast a few degrees below normal for late August. Persistent storms will keep high temperatures in Houston and New Orleans in the upper 80s through at least early next week.

While the Gulf Coast has seen some relief, the same cannot be said for the interior South. Tuesday’s front will finally change that.

Atlanta, for example, has had only two days this summer where temperatures hovered around 80 degrees Fahrenheit. Tuesday could be the first time since July that the city will feel those late September temperatures.

These autumn temperatures will continue throughout next week in the south, with a chance of stormy weather every day.