Wednesday, February 2, 2011

Official 2011 Twin Cities Groundhog Report

Posted by Kirk
The 2011 Report:

Today, Wednesday February 2nd is Groundhog's Day, here's your official Twin Cities Groundhog Report.

At 9:00 this morning, it was -0.8 °F and there was a very light breeze from the North Northwest. A real groundhog would never wake up in such cold weather lest it risk sure death so our stand-in groundhog Stuffed Stanley is the official groundhog of record.

We took Stanley outside and he did indeed cast a shadow as the sun rose above the tree tops in a cloudless sky.

According to legend, the sudden appearance of the shadow scares the groundhog back into hiding and we will have six more weeks of winter. Thus, the official prognostication issuing from the Twin Cities Naturalist office is that winter will end in the Twin Cities on March 16th.

Celestially, February 2nd is an important day. According to the solar calendar, it should mark the end of winter and the beginning of spring.

Forty-two days ago was the winter solstice, the day of the year when we have the least sunlight. From that day on, the amount of daylight increases until the day when there are equal amounts of night and day. We call this day the equinox and it falls around March 21st. Traditionally, December 21st has been known as mid-winter just as June 21st is known as mid-summer. February 2nd falls half way between mid-winter and the equinox so in theory it should mark the end of winter and the beginning of spring.

Has anyone seen any crocus flowers blooming?

Obviously the winter solstice is not really mid-winter. Why do we call the solstice mid-winter if it is also the day we say winter begins? This has long been a puzzle and even caused a few arguments between astronomers and meteorologists. The answer is something we call the lag of the seasons and it affects Groundhog’s day as well. Yes, it is true that Groundhog’s day technically marks the beginning of spring from a celestial point of view but our experience tells us otherwise. Our seasons lag behind what the sun tells us in the sky.

Saying spring starts on Groundhog’s day is a little like saying a frozen dinner is ready to eat as soon as it is pulled out of the freezer. The northern hemisphere has been cooling down for months by the time the solstice arrives. Forty-two days with just less than a minute more sunlight each day is not enough to thaw out the frozen landscape into a lush vernal garden.

The established pattern of cold weather continues for weeks after the beginning of the increase in daylight. This lag makes it seem like mid-winter actually falls on Groundhog’s day rather than the solstice. Rest assured though that on Groundhog’s day, even if it feels like the middle of winter, we are getting an hour and seven minutes more daylight today than we did just forty-two days earlier.

Groundhog’s Day may mark the beginning of spring according to the sun but it will be about forty-two more days until we feel the change. It may seem like winter has a grip on the land but the sun has been working hard to reverse the trend for over a month and we’ll soon start to see those effects.

Incidentally, the legend tells us that if the groundhog sees its shadow it will be scared back into the den and we’ll have six more weeks of winter. How many days are there in six weeks? Forty-two.