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Groundhog Day: Spring Coming Earlier

By Climate Central

Since 1887, Punxsutawney Phil has been predicting each February 2 whether or not an early spring was ahead. Legend states that when Phil does not see his shadow, an early spring is on the way. Otherwise, there will be six more weeks of winter.  Phil saw his shadow last year, and he has only failed to see his shadow 18 times. This week, we examine the trend in the temperature during the six-week period that follows Groundhog Day — in most places, that period is getting warmer.


Temperature trend in the 6-week period that follows Groundhog Day in these U.S. cities

According to the Punxsutawney Groundhog Club, the observance may have its roots in Candlemas Day, which is also on February 2. One old English song proclaims:

If Candlemas be fair and bright,
Come, Winter, have another flight;
If Candlemas brings clouds and rain,
Go Winter, and come not again.

Interestingly, of those 18 times Phil has not seen his shadow, 13 have come since 1970. But no matter what Phil sees on any given year, there is one clear trend — the overall temperature of the planet is going up. The warming that has resulted from the increase in greenhouse gases has led to spring coming earlier across the country.

Earlier spring may sound nice at first, but it comes with an increased risk to agriculture. Fruit trees need a set amount of cold to become dormant over the winter, or they may bloom too early in the year. Thus, an early bloom followed by a quick early season freeze can cause tremendous damage to crops. This was seen last year in the Southeast with a freeze in the middle of March. While March freezes are not climatologically unusual in the Southeast, many crops had bloomed more than three weeks early due to the very warm February. Damage was especially heavy to peaches, blueberries, strawberries and apples, with losses estimated at $1 billion.

Methodology: To determine the temperature for the six weeks following Groundhog Day, the average temperature from February 2 through March 16 was determined for each market from from rcc.acis.org.