Groundhog Day Forecasts: Accurate or Amiss?

Punxatawney Phil
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Every year on February 2, thousands gather at Gobbler's Knob in Punxsutawney, Pennsylvania to find out what weather lies in store for winter's second half. But, can you take stock in what Punxsutawney Phil predicts, or is the celebration little more than February folklore?    

Rooted in Folklore

Yes, Groundhog Day's beginnings do originate from ancient weather folklore, but this doesn't necessarily debunk the celebration. After all, all lore, even if untrue, is based in a grain of truth.

The grain of truth that links the groundhog to weather forecasting is the animal's den emergence and sheltering habits in February and March—a time of year the ancient Europeans believed to be special because of its ties to the spring equinox. 

February 2 is the half-way mark between winter's start and the spring solstice. When they settled in what would become the state of Pennsylvania, they brought this tradition, and soon noticed that the groundhog (which was plentiful there) also shared a connection with the date. They noticed that in February, creatures would awaken from hibernation and temporarily emerge to look for a mate; then in March, they'd come out of their hibernation state for good. It's easy to see how ancient cultures linked this behavior to nature—if the groundhog emerged only for a short period, it's hibernation (and winter) wasn't yet over, however, if it emerged for an extended length, it's hibernation had ended (and spring was at hand). As in today's lore:    

If Phil sees his shadow, it means six more weeks of cold and winter weather for the U.S. But, if Phil doesn't see his shadow, expect unseasonably warm temperatures and the arrival of an "early" spring—springlike weather before the March equinox date.

Guided Forecasts

But just because the groundhog has a good internal clock, that doesn't mean he qualifies to be a meteorologist. You might not know this, but Phil doesn't even issue his own forecasts! 

Contrary to what you may think, Phil isn't set free and watched to see whether he roams about or scurries back underground. No, instead he is said to convey his prediction by chatting with the president of the Punxsutawney, PA Groundhog Club in "Groundhogese." During the conversation, Phil directs the president to one of two scrolls (each holding a different prediction). The president then proceeds to read aloud from the scroll Phil chooses.    

Groundhog Day Forecasts vs. Actual Temperatures

To put the groundhog's skill to the test, let's consider Phil's long winter/early spring predictions side-by-side with the February and March temperatures that the U.S. actually experienced.

In 2016, Phil's forecast was spot on. He forecast an early spring, and the remainder of February not only was above-normal but ranks as the seventh warmest on record for the U.S.

March, too, was mild. Each of the lower 48 states had temperatures that were warmer than the average for March. In fact, it was their top third warmest on record, while it was the fourth warmest March for all of the U.S., Hawaii and Alaska included.    

When you look at Phil's predictions for the past ten years and compare it to national temperatures for February and March data the NOAA National Center for Environmental Information, Punxsutawney Phil has gotten the forecast right 50% of the time. (When looking at his success rate since 1887, this number drops to the 30-40 percent range.)  

Year Shadow Feb Temperatures March Temperatures Phil Correct?
2016 No Above Average Above Average Success
2015 Yes Slightly Below Above Fail
2014 Yes Below Slightly Below Success
2013 No Slightly Above Slightly Below Fail
2012 Yes Above Above Fail
2011 No Slightly Below Above Success
2010 Yes Below Above Success
2009 Yes Above Above Fail
2008 Yes Slightly Above Slightly Above Fail
2007 No Below Above Success
How Accurate Were Phil's Predictions from 2007-2016?
Shadow No Shadow No Record
More Winter 102
Early Spring 18
N/A 10
Groundhog Predictions Since the 1880s