Groundhog's Day

Sunday
February 2, 2014

According to folklore, if a groundhog emerges from its burrow and sees its shadow, six more weeks of winter will follow. If there is no shadow to be seen, then spring will come early.

But how reliable are the little critters?
Let's investigate!

Defining Spring and Winter

Snowfall and temperature can both be used to determine what qualifies as "spring" and what qualifies as "winter". For a full read on how I get the parameters, Check out "Operation Abominable Snowman". The following are the end results:

An early spring occurs when…

After the second week of February, if the last snow for more than two weeks occurs by about March 2nd, AND the average high temperature during the first half of March exceeds 42 degrees.

OR

After the second week of February, if the last snow for more than two weeks occurs after about March 2nd, AND the average high temperature during the first half of March exceeds 51 degrees.

A normal winter occurs when…

After the second week of February, if the last snow for more than two weeks occurs by about March 2nd, AND the average high temperature during the first half of March remains below 42 degrees.

OR

After the second week of February, if the last snow for more than two weeks occurs after about March 2nd, AND the average high temperature during the first half of March remains below 51 degrees.

Evaluating the Groundhogs

Applying this to the last nine years, we get the following results for Kingston:

2005… T= 39.5, Sn= March 23 … Winter
2006… T= 47.1, Sn= March 02 … Spring
2007… T= 42.5, Sn= March 16 … Winter
2008… T= 48.3, Sn= March 01 … Spring
2009… T= 45.1, Sn= March 02 … Spring
2010… T= 49.7, Sn= March 03 … Spring
2011… T= 46.8, Sn= March 23 …. Winter
2012… T= 55.5, Sn= March 02 …. Spring
2013… T= 44.9, Sn= March 19 …. Winter

Thus, in evaluating some of the region's groundhogs, we get the following accuracy ratings for 2005-2013:

—Punxsutawney Phil…

Accuracy: 11%
Correct prediction(s) made in: 2005.
2014 Forecast: "Six more weeks of winter"

—Buckeye Chuck…

Accuracy: 38%
Correct prediction(s) made in: 2008, 2010, 2012.
(Chuck started in 2006, there was no 2005 forecast)
2014 Forecast: "An early spring"

—Staten Island Chuck…

Accuracy: 67%
Correct prediction(s) made in: 2008, 2009, 2010, 2012.
(Chuck started in 2008, there were no 2005-2007 forecasts)
2014 Forecast: "Six more weeks of winter"

Date of last Snow

Average high
Temperature
(March 1-16th)
Outcome
by ~March 2nd
>51 Early Spring

>42
If temp. > 51, then Early Spring
If temp. < 51, then Normal Winter
after ~March 2nd <51 Normal Winter
<42
If temp. > 42, then Early Spring
If temp. < 42, then Normal Winter

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