Nature on the Edge of New York City: Is the Groundhog a Good Weather Forecaster?

Groundhog Day Background and Folklore

From NOAA

Every February 2^nd crowds gather at Gobbler's Knob, in Punxsutawney, Pennsylvania. A groundhog, Punxsutawney Phil, burrowed inside his heated simulated tree trunk, is about to thrust or be pulled into the limelight at about 7:25 am once again. The gates open at 3:00 a.m., followed by live entertainment, music and a pre-dawn fireworks display helps to ignite (hopefully not literally!) the crowd that has gathered in anticipation of Phil's forecast. The awe-inspiring fireworks are set to lively music, which is just what the crowd generally needs on a cold rural Pennsylvania morning. Phil, and others like him, makes the most celebrated weather forecast of the year usually around the crack of dawn. Has spring sprung when Phil emerges from his burrow and doesn't see his shadow? Or should he scurry back into his burrow for six more weeks of winter weather if skies are clear and fair?

Groundhog Day has its origins in an ancient celebration of a point mid-way between the Winter Solstice and the Spring Equinox. Superstition has it that fair weather was seen as forbearance of a stormy and cold second half to winter. The early Christians in Europe established the custom of Candlemas Day, when the clergy would bless candles and people would light them in each window of their homes to ward off the darkness of mid-winter.
But the legend of the February 2^nd forecast also persisted, as captured in this old English saying:

If Candlemas be fair and bright,
Winter has another flight.
If Candlemas brings clouds and rain,
Winter will not come again.

The trail of groundhog history actually leads back to Clymer H. Freas, city editor of the Punxsutawney Spirit newspaper. In 1887, he was inspired by a group of local hunters and gourmets who held a groundhog hunt followed by a picnic barbecue of, well, you know. Anyway, Freas thought it so much fun that he wrote up the group as the Punxsutawney Groundhog Club and went on to promote the Punxsutawney Groundhog as the official weather forecaster. As he embellished the story year after year, other newspapers picked it up and soon everyone looked to Punxsutawney Phil for the critical prediction of when spring would return to the nation.

Historical Track Record of Punxsutawney Phil 1887–2012
Courtesy of Punxsutawney Groundhog Club

Saw Shadow	No Shadow	No Record
100	16	9

Punxsutawney Phil Vs. the U.S. National Temperature 1988–2012

The table below gives a snapshot by year since 1988 whether Phil saw his shadow or not along with the corresponding monthly national average temperature departures for both February and March. The table shows no predictive skill for the groundhog during the most recent years of this analysis. Since 1993, the U.S. national temperature has been above normal 11 times in February, 12 times in March, below normal 6 times in February, 3 times in March, and near normal 3 times in February and 5 times in March.

Year	Shadow	February Temperature Departure	March Temperature Departure
2012	Yes	Above	Above
2011	No	Slightly Below	Slightly Above
2010	Yes	Below	Above
2009	Yes	Above	Slightly Above
2008	Yes	Slightly Above	Slightly Below
2007	No	Below	Above
2006	Yes	Above	Above
2005	Yes	Above	Slightly Above
2004	Yes	Below	Above
2003	Yes	Below	Above
2002	Yes	Above	Below
2001	Yes	Slightly Above	Tied Average
2000	Yes	Above	Above
1999	No	Above	Above
1998	Yes	Above	Below
1997	No	Above	Above
1996	Yes	Above	Below
1995	No	Above	Above
1994	Yes	Below	Above
1993	Yes	Below	Above
1992	Yes	Above	Above
1991	Yes	Above	Above
1990	No	Above	Above
1989	Yes	Below	Above
1988	No	Below	Above

In 2012, the contiguous United States (CONUS) average annual temperature of 55.32°F was 3.25°F above the 20th century average, and was the warmest year in the 1895-2012 period of record for the nation. The 2012 annual temperature was 1.0°F warmer than the previous record warm year of 1998. During February, the contiguous United States experienced above-average temperatures with a national average temperature of 37.7°F. This was 3.5°F above average, making it the 16th warmest February on record. Record and near-record breaking temperatures dominated the eastern two-thirds of the nation and contributed to the warmest March on record for the contiguous United States, a record that dates back to 1895. The average temperature of 50.33°F was 8.57°F above the 20th century average for March and 0.56°F warmer than the previous warmest March in 1910. Of the more than 1,400 months that have passed since the U.S. record began, only one month, January 2006, has seen a larger departure from its average temperature than March 2012. Take a look at the February and March 2012 maps which give a pretty good idea on the distribution of temperatures across the United States. It really isn't a "bright" idea to take a measure such as a groundhog's shadow and use it as a predictive meteorological tool for the entire United States.