1. Bill Murray was bitten by the groundhog twice during shooting.
2. Director Harold Ramis originally wanted Tom Hanks for the lead role, but decided against it, saying that Hanks was "too nice."
3. Tori Amos was considered for the role of Rita.
4. A family of groundhogs was actually raised for the production.
5. One of the groundhog officials is Brian Doyle-Murray, one of Bill Murray's five brothers.
6. The movie was filmed in Woodstock, Illinois. In Woodstock, there's a small plaque that reads "Bill Murray stepped here" on the curb where Murray continually steps into a puddle.
7. According to an interview with director Harold Ramis, he and Bill Murray argued over the tone of the film. Murray wanted the film to be more philosophical while Ramis wanted it to be more comedic. The two argued throughout the production and have not spoken to each other since.
8. On February 2, 1993 the sun didn't rise until 7:25am in Punxsutawney, Pennsylvania. This means the film is technically inaccurate - it would still have been dark at 6am.
9. According to director Harold Ramis, most of the times when he tried to explain a scene to Bill Murray, Murray would interrupt and ask, "Just tell me - good Phil or bad Phil?"
10. In the "Jeopardy!" sequence, the second player we see is Jim Scott, a five-time "Jeopardy" Champion who won his fifth game on the October 1, 1990 broadcast. He went on to win the Tournament of Champions contest that season.
11. There are exactly 38 days depicted in the movie either partially or in full.
12. They shot 25 takes of the closing scene when Bill Murray wakes up next Andie MacDowell as they were unsure of the tonality of the scene.