'False Fall' is trending again. Is there any truth to it?

Unseasonably cool weather led to "False Fall" once again trending on social media. But what's the actual science here? Is False Fall actually a thing?

Earlier this week, temperatures across the Midwest and the Northeast felt more like fall than late summer, as many people woke up to chilly mornings. In the coolest spots on Wednesday and Thursday of this week, some areas were as much as 20 degrees lower than average for this time of year.

State College, Pennsylvania, home to AccuWeather's global headquarters, recorded a low temperature of 49 degrees Fahrenheit on Tuesday—the lowest temperature recorded during August since 2000. Even Starbucks got in on the fall fever, bringing its famed Pumpkin Spice Latte back to United States menus two days earlier than in 2023.

All the unseasonably cool weather led to "False Fall" once again trending on social media. NYBucketList's Instagram claims that coming off of "Hell's Front Door" earlier in the summer, Gothamites are now contending with "False Fall," followed predictably by "Second Summer" for September and October.

False Fall isn't just confined to the northern states either. It's a nationwide phenomenon. Alabama comedian Matt Mitchell posted a viral video in which he takes on different characters as he defines False Fall.

"It's like regular fall, but it only lasts as long as a smile on [longtime Alabama football coach] Nick Saban's face," he said in the video.

But what's the actual science here? Is False Fall actually a thing?

'A steady progression downwards'

Jesse Ferrell, AccuWeather meteorologist and digital producer, noted there is no strict definition for a False Fall. He said the conditions happen when a period of unusually warm weather, often higher than the normal average, is followed by a cooler period. Then things can turn back the other way, leading to what people coin "Second Summer."

"There can be several of each during the months of August through November at any location that experiences a change of seasons," Ferrell explained.

The key here is that on a larger scale, temperatures gradually drop as we move from summer to fall.

"For any one point, a graph of an average of hundreds of years of temperatures shows a slow and steady progression downwards from summer heat temperatures into chilly autumn days," he said.

This is why by the time September rolls around, parents send their kids to school with jackets, and summer camp can't continue perpetually, at least not in colder states.

That said, averages are never a neat thing. Ferrell said that as we transition into the fall season, temperatures over days and weeks cycle back and forth. Cold fronts sweep through cities, ushering in cooler weather, before going back to another peak.

The most recent cool snap in the Northeast and Midwest will soon give way to a warming trend over the weekend and may end with a summer-heat surge in some areas of the Northeast next week, AccuWeather meteorologists said.

Now it's time for the West Coast to get in on False Fall action, where cities like Redding, California, that have been dealing with 90s and triple-digit heat since early June, will have temperatures only in the 70s on Saturday.

A case study in the city of brotherly love

As a further example of what can happen as the seasons transition, Philadelphia experienced near-record highs in the early part of September last year. By mid-month, the city had a stretch of two weeks with average or even below-average temperatures—just in time for the first day of fall on Sept. 23. But then, Second Summer delivered a blow to False Fall, and a sweltering Philly was back in the ring like Rocky.

"Residents bought pumpkin spice lattes and put out the Halloween decorations and were then disappointed by a week of highs in the 80s when the trend reversed and delivered much warmer temperatures the following week," Farrell said.

That's the skinny on False Fall. The seasons will always inevitably change, and fall—and later winter—will always come.