Continuity mistake: When Phil comes around the corner, just before meeting Ned, there are two women walking together in the background. The one in blue is holding a yellow sign upside down that says Phil (the groundhog, not the character). The first 3 days in a row they are together as they should be. On the fourth day and every day thereafter the woman in blue is by herself which does not follow the exact day sequences.
Picture added by Cochrane