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The Science Behind Groundhog Day

Image: Wikimedia Commons

Groundhog Day is a “cross-quarter day” on the celestial calendar. Cross quarter days are mid-way points between the Solstices and Equinoxes. These days are associated with many familiar holidays whose astronomical roots have largely been forgotten. The first cross quarter day of the year is in the period of Feb 2-6 and traditionally known as Candlemas, Groundhog Day, Imbolc (Celtic for “in milk”), St. Brigid’s Day, or Setsubun (Japan). Our current dates of celebration of these holidays are not exactly on quarter or cross-quarter days because these holidays have now been “fixed” in the calendar whereas in the past their coming was marked by actually observing (or at least estimating) the occurrence of a particular position of the Sun along the ecliptic (i.e., observing the arrival of the solstice or equinox).

Sites such as Stonehenge in the UK are believed to be examples of “πobservatories.” The Maya in Central America and the Native Americans at the Cahokia mounds near St. Louis created similar “solar observatories” in their city/temple complexes, which were laid out on strict astronomical lines.

The traditional Japanese Lunar Calendar uses cross-quarter days to mark the start of the various seasons, unlike here in the west where we say that the first days of the seasons coincide with the Equinoxes and Solstices. In the traditional Japanese calendar, the first day of spring (Risshun) is on the first cross-quarter day (February 3 or 4 - time of the traditional Setsubun festival which used to mark the beginning of the new year), summer begins on May 6 (Rikka), autumn on August 8 (Risshuu), and winter on November 7 (Ritou). If the Quarter Days start a season on the cycle (Winter Solstice starts winter, Spring Equinox starts spring, etc.), the Cross Quarter Days mark the high point of each season. The old-timers say that you should have half your hay and half your wood on Candlemas (Imbolc).

Imbolcis sacred to the Celtic fire-Goddess Brighde, "the Bright One" also known as Bridget, Brigid, Brigantia Britain and Bride. Bride was a Sun Goddess who presides over the hearth and smithy, over the inspiration and skill of sacred art and craft, and over the world of crops, livestock, and nature. In particular she is important to sheep who (on the British Isles) begin to lamb at this time of year. The starting of their lactation is a sign that Imbolc is near. Milk has always been important to Bridget. You can see her above the south western door of the tower on Glastonbury Tor, milking a cow. 

Another “holiday” around the time of Imbolc is Groundhog Day. Groundhog Day has to do with the Sun and whether it shines or not, and whether the groundhog sees its shadow. There are shadow paths that have been found in Britain where, due to a gently downward curvature of the land, a single standing stone casts a shadow that is half a mile long! Shadows and light play an important role in any sacred space, and the lowly American groundhog has become the recipient of a much older, probably European, tradition. Another connection between Groundhog Day and Imbolc has to do with weather prediction aspect of this day in early February. “Will winter end soon or will it drag on?” The superstition arose that if the weather was fair on Imbolc, the second half of the winter would be cold and stormy, but if the weather was cold and overcast or stormy, the second half of the winter would be mild. Similarly, if the Groundhog sees his shadow, he will return to his den for six more weeks of hibernation through the coming winter days; however, if the day is cloudy, he will remain out of his den and the weather will be fair.

Groundhog Day traditions in the United States seem to center around the (in)famous Punxsutawney Phil, who lives on Gobbler’s Knob in Punxsutawney, Pennsylvania. According to their official website, “Pennsylvania’s earliest settlers were Germans and they found groundhogs to in profusion in many parts of the state. They determined that the groundhog, resembling the European hedgehog, was a most intelligent and sensible animal and therefore decided that if the sun did appear on February 2nd, so wise an animal as the groundhog would see its shadow and hurry back into its underground home for another six weeks of winter.”

What’s it going to be this year? Perhaps Phil will tell us.

Article by: W. Jerrold Samford, Environmental Compliance Specialist, Troutman Sanders.