There are many ways to mark the changing of the seasons. The modern calendar uses the solstices and equinoxes. Winter begins on the December solstice, for example, and ends on the March equinox.
In many cultures, though, those dates marked the mid-point of a season. The seasons changed roughly halfway between them — dates known as cross-quarter days.
One of those days was marked in early February. In ancient Scotland and Ireland, for example, it came around February 1st. It was known as Imbolc. It was a day to celebrate the arrival of the longer, warmer days of spring.
The early Christian church adopted its own celebration of the cross-quarter day. Known as Candlemas, it was the 40th day of Christmas — the official end of the celebration for some denominations. Candles were blessed on that day — providing light for the entire year.
One of the traditions of Imbolc was to watch the dens of snakes and badgers to see if they stuck their heads out to sample the weather. If it was cold and clear, the critters retreated to wait out a few more weeks of winter. If it was warm and cloudy, though, it was time to head out. A similar tradition was associated with Candlemas.
That tradition is preserved in a modern celebration of the cross-quarter day: Groundhog Day. There’s no correlation between the folklore and the actual weather. Still, it preserves a bit of astronomical tradition — the tradition of cross-quarter days.