Featured Map: Groundhog Day in Punxsutawney (2 February 2011)

Groundhog Day, celebrated today in the United States and Canada, is a day on which a groundhog (Marmota monax) emerges from its burrow and prognosticates an imminent end of winter if the skies are cloudy—or six more weeks of winter if the day is sunny and the groundhog sees its shadow. Punxsutawney, Pennsylvania (the subject of today's featured map) is home to the burrow of Punxsutawney Phil, probably the most famous groundhog.

No doubt residents of the midwestern United States, in the midst of a blizzard with heavy snows and high winds, are hoping very much that the storm will hide the shadow of the groundhogs and that winter will indeed quickly end. The Great Circle Mapper pages for many large airports in the United States feature links to flight delay information from the FAA's Air Traffic Control System Command Center (ATCSCC), including Pittsburgh International Airport, 76 miles to the southwest of Punxsutawney.

Using a groundhog to forecast the end of winter may not be scientific but the date of the occasion has roots in science: it falls midway between the winter solstice and the spring equinox in the northern hemisphere, and thus is the midpoint of the northern winter season. More ancient holidays at about the same time include Imbolc, the beginning of spring in the Celtic calendar (which became St. Brigid's Day in modern Ireland), and the Christmian holiday Candlemas.

Additional information:

• Groundhog Day: The Official Website of the Punxsutawney Groundhog Club
• Groundhog Day – Wikipedia
• Marmota monax (Linnaeus, 1758) – Encyclopedia of Life
• Marmota monax (Linnaeus, 1758) – Catalogue of Life
• Punxsutawney Municipal Airport