Banner Elk, North Carolina, is home to the largest festival celebrating this.
Weather-predicting Wooly Worms
Wooly worms have been part of Appalachian folk lore for hundreds of years; the wooly worm is the caterpillar version of the Isabella tiger moth. The black and brown stripes on it are supposed to predict the weather--the more black fuzz, the harsher the winter.
The Wooly Worm Festival in Banner Elk, North Carolina, attracts thousands of visitors to watch as thousands of worms are narrowed down to just one winner. The winning worm has the distinction of predicting the weather for the nearby ski resort. Worms, with the help of their owners, climb a length of string in a race to the top. Competitors include Dale Wormhardt, Wormy Daniels, Willy the Wonder Worm, and many more. The winner wins a thousand dollars.
In case you’re wondering, there’s a lot of varying science as to how effective wooly worms are at predicting the weather. A lot of evidence suggests, no, it’s not a real thing. But one study found the worms are 85% effective.