Indian summer

Having Indian summer weather at the moment has led me wondering as to where the phrase originates. Unseasonably warm autumn weather in England, used to be called St Martin’s summer (it usually ended by St Martin’s day – 11th November) before the American phrase “Indian summer” gained popularity early in the 20th century. Suggested reasons for the origins of the phrase are:

• It was the period when Native Americans first harvested their crops
• The haziness during this time was caused by prairie fires in the autumn
• Raids on European colonies by Native American war parties tended to end in the autumn.