The logic is poetic: In many indigenous cultures, the veil between the world of the living and the dead was thought to thin during the liminal period between seasons. The warm air was the breath of ancestors returning briefly before the long sleep of winter. The haze was not smoke, but the presence of spirits.
During this week of mild weather, tribes would stockpile their final resources. They would hunt game (deer and bear) that were fat from the fall harvest, and gather the last of the nuts and berries. More specifically, this was the time to set large controlled fires to clear underbrush. The resulting smoke would drift over the horizon, visible for miles. To the European settlers watching from their stockades, the haze on the horizon looked like “Indian” fires—thus, the smoky weather became Indian Summer . indian summer origin