What is the origin of "Indian Summer" and is it offensive?

Etymonline has the first usage dated as 1778.

"spell of warm weather after the first frost," first recorded 1778, American English, perhaps so called because it was first noted in regions inhabited by Indians, or because the Indians first described it to the Europeans. No evidence connects it with the color of fall leaves or a season of Indian attacks on settlements. It is the American version of British All-Hallows summer, French été de la Saint-Martin (feast day Nov. 11), etc. Also colloquial was St. Luke's summer (or little summer), period of warm weather occurring about St. Luke's day (Oct. 18).

It is a very common saying and I have never known a scenario in which its use has caused offence.

If I found someone offended by it, I'd question them more than myself to be frank.

There was a recent article on the BBC news site about this. There's no suggestion at all that it could be considered offensive.

The article confirms its US origin, as there was an alternative term that was previously in use in the UK, "Saint Martin's Summer":

In the UK the original term for a period of unseasonable warmth and sunshine in late September, October or November was described as a Saint Martin's Summer (referring to St Martin's day on 11 November). This term was used throughout much of western Europe.

There's also a suggestion of a possible etymology, that it had something to do with native American hunting traditions, however, it doesn't assert this very strongly or give any source for the claim.

During the beginning of the 19th Century, the American phrase "Indian Summer" became better known. Although the exact origins of the term are uncertain, it is thought to have been based on the warm and hazy conditions in autumn when native American Indians chose to hunt.

Perhaps the source for this is the National Weather Service in the US. Several other possible derivations are suggested there:

Other possibilities include; the Indians made use of the dry, hazy weather to attack the whites before the hard winter set in; that this was the season of the Indian harvest; or, that the predominant southwest winds that accompanied the Indian Summer period were regarded by the Indians as a favor or "blessing" from a "god" in the desert Southwest. Another idea, of a more prejudicial origin, was that possibly the earliest English immigrants equated Indian Summer to "fools" Summer, given the reliability of the resulting weather. Finally, another hypothesis, not at all in the American Indian "camp" of theories, was put forward by an author by the name of H. E. Ware, who noted that ships at that time traversing the Indian Ocean loaded up their cargo the most during the "Indian Summer", or fair weather season. Several ships actually had an "I.S." on their hull at the load level thought safe during the Indian Summer.

Because articles on the BBC News website can be transient, I'm taking the liberty of posting the referenced article here. - TrevorD

September 2013 started on a cool and rather autumnal note - especially across the north of the UK. However, with conditions becoming more summer-like again during this week, many are wondering if this is an Indian Summer in the making.

Traditionally, an Indian Summer is a spell of above-average temperatures accompanying dry and sunny weather after the end of summer. In fact, it is only a true Indian Summer if a warm spell occurs after one, or a series of sharp frosts, and is associated with late-September to mid-November.

In the UK the original term for a period of unseasonable warmth and sunshine in late September, October or November was described as a Saint Martin's Summer (referring to St Martin's day on 11 November). This term was used throughout much of western Europe.

During the beginning of the 19th Century, the American phrase "Indian Summer" became better known. Although the exact origins of the term are uncertain, it is thought to have been based on the warm and hazy conditions in autumn when native American Indians chose to hunt.

Although this week will bring plenty of fine, dry and settled weather across the UK with temperatures above average for the time of year, it is too early to call it an Indian Summer. Predicting whether or not a true Indian Summer will occur during the autumn is not so straight forward and there is no statistical evidence to show that such a warm spell tends to recur each year.

The most recent Indian Summer of note was in 2011 when a new UK October record high of 29.9C (86F) was set in Gravesend, Kent on 1 October beating the previous record of 29.4C. The highest November temperature was 21.1 °C (70F) which was set back in 1938 on 2 November in Essex and Suffolk.

A hot spell in the autumn can arise when the remnants of old Atlantic Hurricanes brings warmth from the tropics in the direction of the UK. The remnants of the hurricane won't necessarily affect the UK directly, but will introduce higher temperatures.

Though it's inaccurate, some people equate the term with "Indian Giver", playing to a stereotype that Native Americans would take back gifts they gave. (Since an Indian Summer often refers to warm weather that returns after cool weather in the Autumn). "Indian Giver" is offensive and so some may take offense through misunderstanding.

In reality, Indian Summer has a variety of different meanings and none of them appear to be offensive. I wouldn't concern myself too much about it.

My guess is that these days just about any phrase you choose will offend someone.

http://www.phrases.org.uk/meanings/indian-summer.html

I think it is a descriptive term for a specific weather condition. Things need names otherwise it is difficult to talk about them. I would use the phrase and not worry.

I would also straight up ask the Cherokee individual what they think of it.

I don't think Indian summer has anything to do with the Indian subcontinent.