This slip up (s) occur during the scene where Henry and his friends are pretend playing at Wrigley after the game. They are on the field with the lights on and it's supposed to be late August according to the movie. However, you can clearly see the breath of Henry's mother and The Rocket as their talking. Late August nights in Chicago are very warm and humid, not cold enough to see your breath. Also, during the same scene, if you look out in centerfield, there is no ivy on the wall where clearly during the game they had that afternoon, there was. This scene was obviously filmed closer to November or December.

Editor's Note: The ivy part is somewhat of a repeat, but the cold, night air is new.