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This film and Edge of Tomorrow (2014) have a character called "Rita," and both films are about men trapped in a never ending day. Also, at the climax, Phil pinches Rita to prove that tomorrow has finally arrived, and in the novel that inspired Edge of Tomorrow (2014), the lead character Cage pinches himself when time first resets. In the novel, Cage awakens at 6 o'clock, like Phil Connors, and he gets Phil's line, "same old, same old." Also, anything new terrified Cage, while Phil has the opposite reaction. Also known as Live, Die, Repeat, Edge of Tomorrow has been described as "Sci-Fi Groundhog Day."
Bill Murray was bitten by the groundhog twice during shooting. Murray had to have anti rabies injections, because the bites were so severe.
According to Director Harold Ramis, most of the time, when he tried to explain a scene to Bill Murray, Murray would interrupt and ask, "Just tell me - good Phil or bad Phil?"
Harold Ramis originally wanted Tom Hanks for the lead role, but decided against it, saying that Hanks was "too nice."
(at around 59 mins) The scene where Phil picks up the alarm clock and slams it onto the floor didn't go as planned. Bill Murray slammed down the clock, but it barely broke, so the crew bashed it with a hammer to give it the really smashed look.
The film was not filmed in Punxsutawney, Pennsylvania, but actually in Woodstock, Illinois (just fifty miles from Bill Murray's hometown of Wilmette, Illinois). There is a small plaque that reads "Bill Murray stepped here" on the curb where Murray continually steps into a puddle. There is another plaque on the building wall at the corner that says "Ned's Corner" where Phil Connors was continually accosted by Ned Ryerson. During the Ned scene the sign for "Woodstock Jewelers" is clearly seen in the background.