Nobody knows for certain how “Indian summer” got its name, but the term dates back to at least 1778 and almost certainly originated in colonial North America. The most widely cited theories connect it to Native American peoples, their hunting seasons, and their descriptions of the weather to European settlers.
The First Written Record
The earliest known use of the phrase appears in Letters from an American Farmer, a collection of essays by French immigrant St. John de Crèvecoeur, written in 1778. Describing the weather in the American colonies, he wrote: “Then a second spring begins; this is what we call the Indian summer, which happens commonly about the middle of November. It is a short season of mild and serene weather…” By the time Crèvecoeur put it on paper, the phrase was already common enough that he used “we call” casually, suggesting it had been circulating in spoken English for some time before that.
By 1820, the naturalist John James Audubon was writing about “The Indian Summer, that extraordinary phenomenon of North America” in his journal, noting a “constant Smoky atmosphere” that irritated his eyes. Audubon suspected the hazy air was caused by Native Americans firing the prairies of the West.
The Leading Theories
Several explanations for the name have survived, and historians haven’t been able to definitively confirm any single one. The main candidates:
- Native Americans described it first. One theory holds that Indigenous peoples were the ones who originally explained the phenomenon to European colonists, and the settlers named it after the source of that knowledge.
- It occurred in Native American territory. The warm spells were first noted by Europeans moving through regions still primarily inhabited by Indigenous peoples, so the geography gave the season its name.
- It coincided with autumn hunting. The warm, hazy conditions in late autumn aligned with the period when Native Americans conducted their final hunts before winter. The Algonquian people in particular were known to use this brief stretch of warmth to gather a last round of supplies before cold set in.
- Prairie fires created the haze. As Audubon speculated, some colonists believed that Native Americans burning prairies for land management or hunting produced the distinctive smoky, warm atmosphere associated with the season.
None of these explanations contradicts the others, and the real origin may involve a combination of them. What’s clear is that the term emerged from the contact between European settlers and Indigenous peoples in eastern North America during the 18th century.
Indigenous Legends About Autumn Warmth
Native American traditions had their own explanations for the phenomenon long before Europeans arrived. The Algonquian people believed the warmth came from a wind sent by their southwestern god, Cautantowwit (the great spirit). Other Native American legends describe a “Life-Giver” who bestowed warm autumnal weather on warriors or communities after great misfortune, such as the loss of crops, giving them a final window to prepare for winter survival.
These stories suggest the weather pattern held real practical and spiritual significance for Indigenous peoples. It wasn’t just a curiosity. It was a last chance to hunt, harvest, and stockpile before the cold locked in.
What the Term Actually Describes
The National Weather Service defines an Indian summer simply as an unseasonably warm period near the middle of autumn, usually following a substantial period of cool weather. That second part is key: a warm week in early October doesn’t count. The warm spell has to come after the first hard frost or a genuine stretch of cold, creating the feeling of summer returning unexpectedly.
The timing varies by latitude. In northern New England, fall color peaks in mid- to late September, while southern regions see it weeks later. Indian summers typically arrive anywhere from mid-October through November, depending on when the first frost hits. Crèvecoeur placed it in mid-November for the mid-Atlantic colonies.
What Other Cultures Call It
The phenomenon isn’t unique to North America. Across Europe, cultures have their own names for the same kind of unseasonable autumn warmth. In much of Western Europe, it’s called St. Martin’s Summer, after the feast day of St. Martin of Tours on November 11. In German-speaking countries, the term is “Altweibersommer,” which translates roughly to “Old Wives’ Summer.” Slavic languages use similar phrases. Each name reflects a different cultural lens on the same meteorological event: a brief, warm reprieve before winter arrives in earnest.
The North American version stands out partly because of its distinctive hazy quality, which colonists and naturalists like Audubon consistently remarked on. Whether that haze came from prairie fires, natural atmospheric conditions, or both, it gave the American Indian summer a character that felt different from a simple warm spell.