MapMuse - Locate Groundhog Day Near You

...sees its shadow because the weather is bright and clear, it will be frightened and run back into its hole, and the winter will continue for six more weeks.

History

Around the fifth century, the European Celts believed that animals had certain supernatural powers on special days that were half-way between the Winter Solstice and Spring Equinox. [citation needed]Folklore from Germany and France indicated that when marmots and bears came out of their winter dens too early, they were frightened by their shadow and retreated back inside for four to six weeks.[citation needed] This was adopted by the Romans as Hedgehog Day.

When Christianity came into being, the formerly pagan observance also came to be called Candlemas.

The earliest known American reference to Groundhog Day can be found at the Historical Society of Berks County in Reading, Pa. The reference was made Feb. 4, 1841 in Morgantown, Berks County (Pennsylvania) storekeeper James Morris' diary: "Last Tuesday, the 2nd, was Candlemas day, the day on which, according to the Germans, the Groundhog peeps out of his winter quarters and if he sees his shadow he pops back for another six weeks nap, but if the day be cloudy he remains out, as the weather is to be moderate."

In the U.S. the tradition derives from a Scottish poem:

As the light grows longer
The cold grows stronger
If Candlemas be fair and bright
Winter will have another flight
If Candlemas be cloud and rain
Winter will be gone and not come again
A farmer should on Candlemas day
Have half his corn and half his hay
On Candlemas day if thorns hang a drop
You can be sure of a good pea crop