In case you’ve missed it, fall has arrived in Vermont. Winding roads and mountain summits are busy with people gawking at the splendor and gathering festive Instagram content.
In past years, early October is already pretty chilly atop the state’s most popular peaks. But these days, you might not have much use for the #sweaterweather hashtag.
It’s unusually warm on Mount Mansfield this year. Temperatures haven’t yet dropped to 32 degrees or below, surpassing the previous record — Oct. 6, 2011 — for the latest first freeze by more than a week and counting.
Wednesday’s low was 55 degrees.
“The daytime highs haven’t been overly high, but it’s just been the fact that overnight, we haven’t really been cooling off a whole lot,” said Robert Haynes, a meteorologist with the National Weather Service in Burlington.
Haynes said this is a common trend in climate data: It’s not so much about daytime spikes, but that temperatures don’t dip as much at night.
The weather service began collecting temperature data on Mansfield in 1955. Across more than six decades, the freezing temperature has, on average, arrived Sept. 15, said Brooke Taber, another weather service meteorologist based in Burlington.
Taber said the first inch of snow generally arrives around Oct. 15.
This pattern on Mansfield, where freezing temperatures have arrived later in recent years, mimics temperature trends at lower elevations, Taber said.
“Lower elevations, Champlain Valley, our first freeze is later in the year and our last freeze is also earlier in the year, so it’s expanding our growing season,” he said.
The Vermont Climate Assessment, a 2014 report by the University of Vermont Gund Institute for Ecological Economics, found the growing season gets 3.7 days longer every 10 years. A longer growing season increases crop productivity, and also increases the geographic area where certain tree species can thrive, such as oak, hickory and red maple. It decreases suitable growing area for spruce and fir trees, which are more tolerant to colder climates.
The weather service doesn’t track temperatures in Smuggler’s Notch. However, the Vermont Agency of Transportation does track when they close Route 108 — the road that winds through the Notch — for winter weather each year.
In 2016, 2017, 2019 and 2020, the permanent winter shutdown began sometime between Nov. 7 and Nov. 19. (The agency didn’t provide data for 2018.)
There are sometimes additional temporary weather closures before the more permanent winter closure, agency spokesperson Amy Tatko wrote in an email.