why is it called indian summer

The term "Indian summer" refers to a period of unseasonably warm, dry weather that occurs in autumn, typically after the first frost and fall equinox, often lasting several days to over a week. The origin of the term is uncertain, but it likely began in the northeastern United States and New England. One theory suggests early settlers associated the hazy warm weather or sun rays through autumn air with Native American campfires. Another explanation is that Native Americans took advantage of these warm periods to gather additional food before winter. The phrase was first recorded in a 1778 letter by a Frenchman describing warm weather in the Mohawk region and later adopted in the UK during the 19th century. The term does not derive from India but from Native Americans and the perception of this late warm spell during autumn.