On February 2, in front of thousands of Groundhog Day celebrants, Pennsylvania's Punxsutawney Phil will emerge from his burrow and either see his shadow—a harbinger of six more wintry weeks—or not, which allegedly portends an early end to winter. Phil's rivals, including Staten Island Chuck and Wiarton Willie, might also predict an early or late spring. Why do Americans, Canadians and others around the world turn to these furry rodents for weather forecasts? Explore Groundhog Day’s shadowy history as well as interesting facts about the custom below.


Falling midway between the winter solstice and the spring equinox, February 2 is a significant day in several ancient and modern traditions. The Celts, for instance, celebrated it as Imbolc, a pagan festival marking the beginning of spring.

As Christianity spread through Europe, Imbolc evolved into Candlemas, a feast commemorating the presentation of Jesus at the holy temple in Jerusalem. In certain parts of Europe, Christians believed that a sunny Candlemas meant another 40 days of cold and snow.

Germans developed their own take on the legend, pronouncing the day sunny only if badgers and other small animals glimpsed their own shadows. When German immigrants settled Pennsylvania in the 18th and 19th centuries, they brought the custom with them, choosing the native groundhog as the annual forecaster.

First Groundhog Day

The first official Groundhog Day celebration took place on February 2, 1887, in Punxsutawney, Pennsylvania. It was the brainchild of local newspaper editor Clymer Freas, who sold a group of businessmen and groundhog hunters—known collectively as the Punxsutawney Groundhog Club—on the idea.

The men trekked to a site called Gobbler’s Knob, where the inaugural groundhog became the bearer of bad news when he saw his shadow.

Nowadays, the yearly festivities in Punxsutawney are presided over by a band of local dignitaries known as the Inner Circle. Its members wear top hats and conduct the official proceedings in the Pennsylvania Dutch dialect. (They supposedly speak to the groundhog in “Groundhogese.”)

Every February 2, tens of thousands of spectators attend Groundhog Day events in Punxsutawney, a borough that’s home to some 6,000 people. It was immortalized in the 1993 film Groundhog Day, which was actually shot in Woodstock, Illinois.

How Accurate Are Groundhogs?

While sunny winter days are indeed associated with colder, drier air, we probably shouldn’t trade in our meteorologists for groundhogs just yet. Studies by the National Climatic Data Center and the Canadian weather service have yielded a dismal success rate of around 40 percent for Punxsutawney Phil.

Staten Island Chuck, on the other hand, is reportedly accurate almost 70 percent of the time.

What About Woolly Bears?

For the last 30 years, residents of Vermillion, Ohio, have turned to a very different creature for their annual weather forecast: the woolly bear caterpillar. According to tradition, if the bugs have more orange than black coloring in autumn, the upcoming winter will be mild.

More than 100,000 people attend the town’s Woollybear Festival, held every fall since 1972.

But woolly bear caterpillars aren’t the best prognosticators, either: While their bands may vary from year to year, researchers have found the variation is due to last year’s weather, not the upcoming winter.

Groundhog Facts

Also known as woodchucks, groundhogs belong to a group of large ground squirrels known as marmots. They grow up to 25 inches long and can live for 10 years in captivity. (According to legend, Punxsutawney Phil is more than 125 years old thanks to the magical punch he imbibes every summer.)

Groundhogs spend the winter hibernating in their burrows, significantly reducing their metabolic rate and body temperature; by February, they can lose as much as half their weight.

When they’re out and about, the bristly rodents eat succulent plants, wild berries and insects—and they don’t mind helping themselves to garden vegetables or agricultural crops.