October is the month of clear skies. We can expect frost several times, and Indian summer days after those frosts. The necessary ingredients for an Indian summer day, or just a few hours in the afternoon, are that the sun must shine, the air should be hazy or a bit smoky and still (or nearly so), and the temperature must be above-normal. These warm, sunny, hazy days always follow autumn’s first frost and occur when a high pressure system is passing through.
The origin of Indian summer is as hazy as the brief “season” to which it refers. Some sources say it was born in New England and referred to the time when Indians made their final preparations for winter. They often burned grassy areas in late fall to flush out game for one final hunt before winter. The burning grasses gave the still autumn air its extra hazy appearance.
Indian summer is rare and that’s why people relish it. Golfers, bikers, picnickers and hikers will be out in numbers. The added lure of autumn colors will bring photographers and landscape painters out. In addition, banded woolybears and leopard frogs cross roads and paths, garter snakes and painted turtles sun themselves, honeybees visit the remaining aster and chrysanthemum flowers, and several species of butterflies will be on the wing. An Indian summer day seems for a few hours to hold back winter’s onset.
Jim Gilbert’s Nature Notes are heard on WCCO Radio at 7:15 a.m. Sundays. His observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.