Some of the best colors of autumn don't come on trees; rather they are found inching along the ground, on sidewalks, across roads and highways. They are the black and rusty brown of the woolly bear, the only caterpillar we know that's more beautiful than the moth it later becomes.

The woolly bear, in addition to (or perhaps because of) being a thing of beauty, has long been a tool of backwoods weather forecasting. It's a user- friendly one, being inoffensive and soft to the touch. By studying it, you are supposed to be able to determine the severity of the coming winter. These divinations have something to do with the width of the woolly bear's front black band as compared with that of the rear black band. It's probably not a good idea to get too scientific about it.

The Hagers-Town Town and Country Almanack in western Maryland is trying to do so, however, at least in a small way. The almanac, which carries long- range weather forecasts among other bits of rustic wisdom that it disseminates to a large readership, has begun charting its annual woolly-bear predictions and comparing them with those done for it by a professor of computer science. So far, the woolly bears seem to be more prescient: their prediction for last winter was right on the nose, according to publishers of the almanac, and the professor's was not.

The almanac has only been doing this for a few years, however, and large segments of the economy probably aren't ready yet to do their planning based on the caterpillars' forecasts. More data are needed, meaning in this case more woolly bears. Unfortunately, most of them are gone for the year, moved on to the cocoon stage. If you want to engage in natural weather forecasting this late in the season, you'll have to do what we do, which is to call travel agents and find out whether the woodchucks are booking January charter flights to Miami.