Last night at library, I picked up a book, authored in the 60s, interviewing folks in the Lower Appalachian Mountains. Whole section given to how the folks predict winter. They don't do the groundhog thing. But, if at this time of year the north side of the bark on trees is dry.. winter is near over. If it is moist, more weeks of winter.
Trees in my local are moist on the north side.
Same thing here in Pittsburgh..... moist on north side. I own a small nursery and I'm out with the earth all the day (except when here).
Those natural ways to predict the weather are very accurate, if you have studied them long enough.