I’m not sure where or when Groundhog Day got started, but farmers in our area used to use this day as a reminder to check their hay and livestock feed supply. If the storage bins were more than half-full, then they were in good shape until spring. If not, then they would need to think about buying more feed because they might run short later on.
This all fits in with phenology, the science of observing natural events in the environment. Phenologists record the dates of things such as when certain flowers bloom or when crickets first start to chirp in the spring.
Information like this, logged over many decades, may show certain trends like earlier blossoming of spring flowers. Data like that could indicate a trend toward a warmer climate.
I remember when I was a little boy listening to farmers saying they needed to plant corn when the oak leaves were the size of squirrels ears. If you look at young oak leaves in the spring, you’ll notice that is just about the right time for field corn to go into the ground. The corn planting date changes somewhat from year to year depending upon weather conditions and that is reflected in the growth rate of oak leaves.
A well-known practical use of phenology is the timing of crab grass control. The blooming of forsythia is the signal for applying crab grass herbicide.
I wonder if professional phenologists argue that Ground Hog Day isn’t really phenology. It probably doesn’t matter too much since meteorologists have already gone ahead and claimed this as their special day.