Groundhog Day is rather strange, when you think of it. Nevertheless, there's a lot of language involved: the who/what/where/when/why of it, concepts around weeks and seasons, conditional if/then regarding if the groundhog sees his shadow, groundhogs themselves and what category they belong to, comparing and contrasting with other animals and their psychic abilities, etc.
It's a good time to point out a resource like Pete's Powerpoint Station, which has a bunch of presentations you can download and review with students. Powerpoint files like these combine text and images and are a nice way to review a topic with students and develop comprehension.
As with any topic related to geography, I was also able to able to find something in Google Earth you could use to discuss the holiday: a model of the stage where Punxatawney Phil will make his appearance. Click this link and you can load the file into Google Earth (which you must have installed first). Use the navigation controls to zoom in (and out, to give a context about where this event takes place) to see the 3D model. It doesn't do anything, really, but is a cool visual anyway.
Here's hoping for fewer than six weeks of winter to go!