Groundhog Day predictions about the coming of spring put the spotlight on Punxsutawney Phil every Feb. 2, but celebrating the midpoint between the shortest and darkest day of the year and the spring equinox has ancient roots in European agricultural life.
Punxsutawney Phil is far from the only groundhog whose human handlers make annual announcements about whether they've seen their own shadows and are predicting six more weeks of winter or an early spring.
The date not only divides the calendar between the winter solstice and the spring equinox - it's also a time of year that figures in the Celtic calendar and the Christian holiday of Cadlemas.
And in eastern and central Pennsylvania, where people of German descent have been watching the groundhog's annual emergence from hibernation for centuries, there's a tradition of groundhog clubs and celebrations that are independent of Phil.
Some dismiss the Punxsutawney event as an unworthy rival to their own festivities, which they say forecast more accurate weather predictions. There have been weather-predicting groundhogs in at least 28 U.S. states and Canadian provinces, and less formal celebrations far and wide.
One thing it's not: serious business.
"We know this is silly; we know this is fun," said Marcy Galando, executive director of the Punxsutawney Groundhog Club. "We want people to come here with a sense of humor."
Celtic people across Europe marked the four days that are midway between the winter solstice, the spring equinox, the summer solstice and the fall equinox. What the Celts called Imbolc is also around when Christians celebrate Candlemas, timed to Joseph and Mary's presentation of Jesus at the Temple in Jerusalem.
Ancient people would watch the sun, stars and animal behavior to guide farming practices and other decisions, and the practice of watching an animal's emergence from winter hibernation to forecast weather has roots in a similar German tradition involving badgers or bears. Pennsylvania Germans apparently substituted the groundhog, endemic to the eastern and midwestern United States.
Historians have found a reference in an 1841 diary to groundhog weather forecasts in early February among families of German descent in Morgantown, Pennsylvania, according to the late Don Yoder, a University of Pennsylvania professor whose 2003 book about Groundhog Day explored the Celtic connection.
Yoder concluded the festival has roots in "ancient, undoubtedly prehistoric, weather lore."
Pennsylvania Germans settled in the area, and in the late 1880s, they started celebrating the holiday by picnicking, hunting and eating groundhogs.
Members of Punxsutawney Groundhog Club, organized in 1899, care for Phil and his woodchuck family at a customized space beside Punxsutawney Memorial Library, where there's a window with a view into the creature's burrow.
The Punxsutawney groundhog makes predictions, but he's not always predictable. The designated groundhog emerged before sunrise in 1929 and didn't come out until late afternoon in 1941.
The 1993 movie "Groundhog Day" caused such a resurgence of interest that two years after it came out, event organizers voiced concern about rowdy crowds drinking all night, people climbing trees and others stripping to their underwear.