Minnesota summers are short, but even shorter are our Indian summers, which may last as little as one day or several days scattered intermittently across the calendar. An Indian summer day is one with an above-normal temperature and little or no wind. These warm, sunny, hazy days always follow autumn's first frost and occur when a high-pressure system is passing through.

The origin of the phrase Indian summer is as hazy as the brief "season" itself. Some sources say it comes from New England, where it was used to refer to the period when American Indians made their final preparations for winter. Indians often burned grassy areas in the late fall, flushing out game for one final hunt before the cold. The burning grasses gave the still autumn air its extra hazy appearance.

Indian summer is rare, and that's why people relish it. Golfers and bikers, picnickers and hikers will be out in numbers. The added lure of autumn colors will pull photographers and landscape painters from their houses. In addition, banded woollybears 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 the coming of winter.

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.