In one scene, Connors throws himself from the bell tower of a high building. This building is actually an opera house in Woodstock, Illinois. Local legend has it that a ghost of a young girl haunts the building since a girl once fell off of the balcony section inside the opera house and died.
Bill Murray was bitten by the groundhog twice during shooting.
On the DVD, Harold Ramis states that the original idea was for him to live February 2nd for about 10,000 years. Later he says that Phil probably lived the same day for about 10 years
Originally, Phil was supposed to murder the groundhog in his lair. This was changed, however, since it seemed too much like Caddyshack.
The idea comes from 'The Gay Science', a famous book by Friedrich Nietzsche. In his book, Nietzsche gives a description of a man who is living the same day over and over again.
Harold Ramis considered Chevy Chase, Steve Martin and John Travolta for the role of Phil Connors, but he considered them as "far too nice" compared to Bill Murray.
There are exactly 38 days depicted in this film either partially or in full.
And if that wasn't enough, there's more.
Have a great Groundhog Day, everyone!