Sir Walter Wally's record no better than a coin flip

Sir Walter Wally predicted 6 more weeks of winter as he saw his shadow Sunday morning at the Groundhog Day celebration outside the North Carolina Museum of Natural Sciences. Groundhog Day is rooted in a German superstition that says if a hibernating animal casts a shadow on the Feb. 2 Christian holiday of Candlemas, winter will last another six weeks. If no shadow was seen, the legend calls for an early spring.

Groundhog Day’s roots lie not just in the Christian holiday of Candelmas but before that in a pagan festival. That festival celebrates the first cross-quarter day, the midpoint between an equinox and solstice. Both celebrate first signs of spring at this time. It’s also when you are supposed get a start on spring cleaning, the fireplace in particular. The other cross-quarter day with Pagan roots that we have a lot of fun with today: Halloween.

Greg Fishel and the rest of the WRAL meteorologists often explain how little validity long range forecasts have. Even those backed up by numerous models generated by Cirrus and Stratus , NOAA’s twin supercomputers are questionable. How accurate can a rodent sourced forecasts be?

The State Climate Office of North Carolina took a look at animal and weather folklore recently across the state. Since it’s not clear what kind of resolution we should expect from woodchuck based prediction systems, we'll assume predictions are Wally… er. Raleigh specific.

Last year, the furry forecaster predicted 6 more weeks of wintry weather. In that 6 week period, Raleigh was down 3.42°F despite a slightly warmer second week. Not bad for a whistle pig. However in 2012 he called also called for more winter, but Raleigh was up 3.08ºF for that period.

Since 2000, Sir Walter Wally has called for more winter 12 times and an early spring twice and has a 50/50 success record on both calls.

Even when I tried to give some credit for how much warmer or colder it was doing those 6 weeks, the numbers still look like a coin flip. Walter was off by an average of -0.03ºF according to the climate office’s numbers for how much Raleigh deviated from temperature averages over that 6 week period.

Before we rename him Sir Walter Coinflip, consider his slightly more famous cousin, Punxsutawney Phil, who has making predictions since 1887. Phil has only 39% record. Sir Walter’s record was good enough to earn him place on The Weather Channel’s “Top 11 Groundhogs to Watch.”