Can hibernating creatures be used to predict the end of winter? Absolutely! Hibernating creatures such as the groundhog sleep throughout winter, and do not wake up until winter is over. Somehow they have an internal body clock that allows them to sleep all winter long, and wake up in spring. The groundhog is no exception to this, and is one of the hibernating animals used to predict when winter will end.
In the U.S, groundhog day is celebrated on February 2, which is a little over six weeks before the astronomical beginning of spring. Astronomically, spring occurs on the vernal equinox, which usually falls on March 20 or 21. February 2, which is groundhog day, therefore falls approximately six weeks before the vernal equinox. So, if you wake up a groundhog on February 2, there is going to be six more weeks of winter, whether he sees his shadow or not. Here is where it gets tricky. The arrival of spring, using groundhogs is based upon using local weather patterns to predict the arrival of early spring or late winter. For example, even though spring oficially starts with the vernal equinox, local weather patterns can 'shorten' or 'prolong' winter. We can have an unseasonably cold spring, and thus 'prolong' winter, or an unseasonably warm winter, and thus 'shorten' winter. If the groundhog is awakened on a day when it is cloudy, it will not go back to sleep, because cloudy weather indicates the arrival of spring weatherwise. If however he is awakened on a sunny day and sees his shadow, he will go back to sleep, because cold, sunny days are indicative of winter. Here is a great article by wikipedia about Groundhog day traditions.
It is amazing how God in His wisdom has given to us all of nature for our enlightenment. If we make it our business to really study nature, and the laws that govern it, then we will see God's hand working in the world He has given to us.