During warm periods of fall such as this, people often throw around the term "Indian summer" when they're raving about the weather. But like so many offhand phrases, people don't always know what exactly it means, let alone where it came from.
When it comes to the origin of the phrase, there is little-to-no consensus or evidence from which to trace a true etymology. One Chicago-area linguistics professor responded to an interview request by simply saying, "I have no idea."
What people can agree on, however, is that the term was probably introduced in the 18th Century to describe the same periods of warmth that exist today. William R. Deedler, a weather historian for the National Weather Service, wrote a 1996 essay on the term and pointed to an exhaustive, early 20th-Century paper written by Albert Matthews that gets as close to the origin as possible.
Deedler said Matthews discovered a 1778 letter written by Frechman St. John de Crevecoeur that describes a period when "rain is followed by an interval of calm and warmth which is called the Indian Summer; its characteristics are a tranquil atmosphere and general smokiness." It mentions the warm period as coming in middle November, after frosting and snow had already begun.
Deedler wrote that several hypotheses exist to explain the "Indian" part of the name. Some believe the mild weather provided native "Indians" with their best opportunities to hunt during that season. Others believe it was the time that ships traversing the Indian Ocean attempted their deliveries. Again, there is no clear way to tell.
Jim Angel, a state climatologist at the University of Illinois, said he had also fruitlessly attempted to discover the phrase's meaning.
"You're right in that there's no consensus. I've actually looked at that in past, to see where did it come from. Now it's kind of like Groundhog Day or one of those that has turned into folklore," said Angel, 52. "Kind of the working definition is some warm period that occurs after the first good hard frost in the fall."
Angel said despite the vague definition, what usually constitutes an Indian summer is the timing (October or November), temperature (60s or 70s) and frost (one must have occurred).
Climatologists wouldn't rely on the term to describe Chicago's current weather, he said, but it certainly qualifies as an "Indian summer."
"There's kind of a nebulus about the term warm. It means different things for different people, but it's getting up into 70s after a nice frost there, so that would be kind of the working term there. I think that would fall into it."
When it comes to the origin of the phrase, there is little-to-no consensus or evidence from which to trace a true etymology. One Chicago-area linguistics professor responded to an interview request by simply saying, "I have no idea."
What people can agree on, however, is that the term was probably introduced in the 18th Century to describe the same periods of warmth that exist today. William R. Deedler, a weather historian for the National Weather Service, wrote a 1996 essay on the term and pointed to an exhaustive, early 20th-Century paper written by Albert Matthews that gets as close to the origin as possible.
Deedler said Matthews discovered a 1778 letter written by Frechman St. John de Crevecoeur that describes a period when "rain is followed by an interval of calm and warmth which is called the Indian Summer; its characteristics are a tranquil atmosphere and general smokiness." It mentions the warm period as coming in middle November, after frosting and snow had already begun.
Deedler wrote that several hypotheses exist to explain the "Indian" part of the name. Some believe the mild weather provided native "Indians" with their best opportunities to hunt during that season. Others believe it was the time that ships traversing the Indian Ocean attempted their deliveries. Again, there is no clear way to tell.
Jim Angel, a state climatologist at the University of Illinois, said he had also fruitlessly attempted to discover the phrase's meaning.
"You're right in that there's no consensus. I've actually looked at that in past, to see where did it come from. Now it's kind of like Groundhog Day or one of those that has turned into folklore," said Angel, 52. "Kind of the working definition is some warm period that occurs after the first good hard frost in the fall."
Angel said despite the vague definition, what usually constitutes an Indian summer is the timing (October or November), temperature (60s or 70s) and frost (one must have occurred).
Climatologists wouldn't rely on the term to describe Chicago's current weather, he said, but it certainly qualifies as an "Indian summer."
"There's kind of a nebulus about the term warm. It means different things for different people, but it's getting up into 70s after a nice frost there, so that would be kind of the working term there. I think that would fall into it."