INDIAN SUMMER. A warm-up after the first frost may or may not be Indian Summer.

All in all, even with the variety of opinions on this weather (or seasonal) phenomenon, the most popular belief of Indian Summer is as follows...It is an abnormally warm and dry weather period, varying in length, that comes in the autumn time of the year, usually in October or November, and only after the first killing frost/freeze. There may be several occurrences of Indian Summer in a fall season or none at all.

In some versions of the tradition, Indian Summer requires a spell of sunny days in the 70s (lower twenties in Canada).

Perhaps the temperature criterion misleads. Indian Summer begins when the orange ladybugs break the hibernation they began at the first frost.