A glimpse of crisp, cool air...then back to summer heat: What to know about 'false fall'

Since August turned to September, people in the Midwest and along the East Coast have gotten a taste of that crisp, cool fall air.

When that break in the summer heat hits, some of us get excited for pumpkin spice lattes, cozy sweaters and apple picking.

But by the end of the week, temperatures in Chicago, for example, reached up to the high 80s again.

September often corresponds with what some of us refer to as "false fall."

It might feel fake to humans, but as AccuWeather's lead long-range expert Paul Pastelok says, these early cool temperatures help signal to the trees that fall is, in fact coming.

Fall foliage predictions: These maps show when and where to see peak colors

‘The trees know’: False fall helps push trees to shut down for winter

“This is a preview, and it's a long preview,” Pastelok told USA TODAY in an interview.

He predicted temperatures in the Midwest and the Dakotas would go back up eight to 12 degrees above the average for several days before returning to the “real thing” later in September.

He said these cool days and nights, however long they last, help the trees to get ready for winter.

“Trees are very smart,” he said, explaining that the shortening days is also a factor for the trees to change, but, “the weather can have a kind of a push on when these trees start to shut down…Getting this week of cool weather, the trees start to notice that kind of stuff. You may start to see things start to shut down a little bit on and a little bit of less green tint in the green trees going forward here in the next week or so.”

Climate change pushing into early 'false fall' temps in some areas

Pastelok said the impacts of climate change can influence fall in different ways depending on the area. For example, in the Northwest, the above-80 temperatures last longer, throwing off the timing of the foliage. Some season changes also vary year by year, he said.

But climate change can throw off other parts of the seasonal ecosystems like the migration patterns of insects and droughts, which can contribute to changing the foliage.

AccuWeather is predicting vibrant fall foliage in the Midwest, Great Lakes and interior Northeast this year.

Severe weather is another symptom of climate change that could impact the foliage.

The tropics have been quiet recently , Pastelok said, so he said he expects there to be more tropical storms in the coming months.

This article originally appeared on USA TODAY: A glimpse of crisp, cool air...then back to summer heat: What to know about 'false fall'