who created groundhog day

The movie Groundhog Day was created by screenwriter Danny Rubin, who came up with the original story and first script, and director Harold Ramis, who worked with Rubin to rewrite the screenplay and direct the film released in 1993.

If by “Groundhog Day” you mean the holiday itself (February 2), that tradition grew over centuries from European Candlemas and weather lore brought by German immigrants to Pennsylvania, not from a single identifiable creator.