Factual error: For a baseball movie, you would think they would have known the rules of the game better. There is a scene in which Henry uses the "hidden ball trick" to pick a runner off of first base. He stands on the rubber on the mound with only the rosin bag in his hand while the first basemen holds the ball. It is a violation for him to stand on the rubber or straddle it without the ball in his hand and is called a "balk". Technically the runner should have been awarded second base.
Factual error: At the end of the film, Amos is shown turning onto I-95 south. However, he does so from an intersection, not an on-ramp. Since interstates are limited-access highways, in reality he would have needed to use an on-ramp to enter I-95.
Factual error: While Meg Ryan is typing her letter to "Sleepless and Son," Rosie O'Donnell is sitting on the couch watching "An Affair to Remember." Any true AAtR fan can easily notice that the film's editing has obviously been altered by the Sleepless director - the scene with Deborah Kerr and Cary Grant leaning on the boat railing actually takes place towards the beginning of the movie, while the scene of them looking up at the Statue of Liberty takes place about four days later. However, in Sleepless, the order of the AAtR scenes shown on Meg's TV are incorrect - Kerr and Grant are leaning on the railing as the sequence starts, then jumps WAY ahead to them staring up at the Statue of Liberty (which then would have been about four days later), and ends with them standing next to the boat's railing again (four days before).
Factual error: When Thomas is at the race track and putting a bet down, the money he's holding is newer, even though the scene takes place in the 60s.
Factual error: When Sharon is being driven by her Dad to the hospital to give birth to her baby ('Snapper'), they drive over a bridge on the River Liffey in Dublin to the south side of the city. However, the Rotunda Hospital, where she gives birth is on the North side of the city, quite a distance away from where they seemed to be headed.Deborah Nolan
Factual error: A shot of the Calgary skyline at night is displayed. The tall building on the left with the glowing roof is Banker's Hall. Also notice the building with the red logo, Canada Trust Tower, that is to the right of it. Neither of these buildings existed at the time of the 1988 Calgary Olympics. Bankers Hall wasn't completed until 1989, and the Canada Trust Tower wasn't completed until 1991. (01:25:16)
Factual error: Phil departs from the office right after the 5pm news. Punxsutawney over 90 minutes' drive from Pittsburgh. The sunset in Punxsutawney in early February is about 5.30pm, so by the time they get there it should be completely dark. But it's bright daylight, without even a hint of twilight. (00:05:45)
Factual error: Although taking place in North Dakota, the Jeep and cop car have the older Illinois plates.