Indian summer evolved over the centuries from a pioneer superstition to the poet’s best friend to the meteorologists’ whipping boy.
It is a period of unusually warm, still days that follow a cold spell. The atmosphere is hazy or smoky, the barometric pressure is high and the nights are clear and chilly.
But it takes place at different times around New England. Indian summer historian Adam Sweeting notes that if it follows a killing frost, then Farmington, Maine, can have one as early as September 28. Block Island in Rhode Island doesn't get a killing frost until November 26.
On average, Concord, N.H., has its first killing frost on October 2, but Hartford, Conn., must wait until October 24.
Then again, some say Indian summer exists more in our imaginations than it does as a meteorological event.
Early Days of Indian Summer
Indian summer has become as much a part of New England as the town common, the white steeple and the covered bridge. But it wasn’t always that way.
A Boston lexicographer named Albert Matthews searched early American literature to find who coined the expression. He found it in a letter written in 1778 by a New York farmer, Hector St. John de Crevecoeur. Matthews, though, surmised people used the expression widely back then.
Before 1820, the concept of Indian summer was more prevalent in the Ohio River Valley – Pennsylvania, Kentucky and Ohio – than in the Northeast.
Samuel Kercheval, in his History of the Valley of Virginia, wrote that pioneers feared the season. “It afforded the Indians -- who during the severe Winter never made any incursions into the settlements -- another opportunity of visiting the settlements with destructive warfares."
Some said the multicolored leaves wear war paint.
Some speculated it got its name because people noticed the warm weather in places where Native Americans lived. Or, they thought, because Indians first described it to Europeans, or because it's the time of year when Indians typically hunt.
Daniel Webster thought the colonial settlers came up with the name because they believed the western Indians started great fires, which created the air's smoky haziness. The western prairies were 'then an unknown and mysterious region of unimaginable area,' reported the Boston Globe in 1927.
It was only after 1820 that the mini-season was consistently tied to New England, according to Sweeting.
“For perhaps a week in early November, New England seems most New England," he wrote.
New England writers seized on Indian summer imagery in the 19th century. It became a metaphor for idyllic beauty before inevitable death, for wizened understanding, for an idealized past when peace settled over a community.
And it was a perfect time for the Pilgrims and Indians to sit down to that mythical Thanksgiving.
In Oldtown Folks, Harriet Beecher Stowe wrote,
...when the warm late days of Indian summer come in, the Deacon began to say to the minister, "I suppose it's about time for the Thanksgiving proclamation," at such times there came over the community a sort of genial repose of spirit.
The Transcendentalists, especially Henry David Thoreau, loved the season. To Thoreau, it represented the hope that springs eternal.
“May my life not be destitute of its Indian Summer," he wrote in 1851, so "I may once more lie on the ground with faith as in Spring."
Emily Dickinson was less cheerful than Thoreau: “A - Field of Stubble, lying sere/Beneath the second Sun. … Is often seen -- but seldom felt, On our New England Farms,” she wrote.
New England writers still used the weather imagery in the 20th century. Peyton Place, by New Hampshire’s Grace Metalious, starts with, “Indian Summer is a woman.” It’s ‘ripe, hotly passionate, but fickle.’
By the 20th century, Indian summer became a meteorological controversy. The question arose: Did it even exist?
In 1937, the Boston Globe reported that, statistically, there is no such thing as Indian summer.
"New England has the idea that, most Falls, we have a period of about two weeks in which we have glorious weather -- halcyon days when the sun is delightfully warm and the air is filled with amethystine haze. Really, this is merely another weather superstition."
Such periods happen only once every 50 years, the newspaper reported.
The Old Farmer’s Almanac insisted throughout the 20th century that Indian summer may only occur between Nov. 11 and Nov. 20.
The Almanac based its argument on an old saying, If All Saints’ (November 1) brings out winter, St. Martin’s Day (November 20) brings out Indian summer.”
The U.S. Weather Service defines Indian summer weather as sunny and clear with above normal temperatures, occurring late-September to mid-November.
The Boston Globe writer who questioned its existence in 1937 couldn’t help but acknowledge its power over our imaginations:
Meteorologically, these Indian Summer days are a condition of extremely delicate balance between the retreating armies of the sun and the advancing hosts of the North. In a sense, the days are a period of truce.
This story was updated in 2019.