Move over groundhogs, another fuzzy creature is aiming to predict winter's reign.

Woolly worms -- black and brown caterpillars of the tiger moth species -- have been known to forecast how severe winter will be, with the colour of each of the worm’s 13 segments corresponding with the 13 weeks between the winter solstice and the spring solstice. The more brown a worm is, the milder the winter, while a blacker worm predicts a harsh season. The insects show up en mass throughout North America in late September and October as they seek hiding places for the coming cold.

To celebrate these prophetic creatures, Banner Elk, North Carolina, located near the Tennessee border, organises a Woolly Worm Festival every October. The highlight of the festival -- this year on 21 and 22 October -- is the woolly worm races, where the insects race vertically up a 42in string. While many participants bring worms found in the wild, the critters can also be purchased for $1 at the festival.

The fastest worm on Saturday wins $1,000 and has the official honour of predicting that season’s weather (the fastest on Sunday wins a consolation prize of $500). Last year’s winner had black ends and a brown middle, predicting a cold start and end to the season and a mild midwinter. The winter turned out mild overall.

Now in its 35th year, the festival has grown to attract more than 23,000 people and more than 140 food and craft vendors. Daily admission costs $5 or $2 for children five to 12. Kids four and under get in free.