Robin had always suspected that “Groundhog Day” was Buddhist inspired.
In Buddhism, you are reborn until you are finally wise and then you can enter Nirvana; in the film, the hero experiences the same day over and over again until he is finally wise and then experiences – the next day.
“This is probably a variation on the same theme,” Robin suspects.

So “Groundhog Day” IS a religious movie, but Buddhist religious, not Christian.