Continuity mistake: When Ellen Brandt is confronting the Police Chief of Rose Hill, TN at the bar. The weapon that is visible that Brandt takes is a semi-automatic with a single stack magazine. The weapon which she shoots has a double stack magazine. (00:54:10)
Continuity mistake: After Tony gets the armor back at the Mandarin's hideout and meets up with Rhodes, they go by boat to the harbor. On the way Tony calls the Vice President - during this scene the VP's phone changes, note the camera on the back of the phone is visible, but in another shot right after, it is a completely flat back panel. (01:30:10)
Continuity mistake: Before Tony sends a holiday greeting to the Mandarin his car is pointed one way when he gets in, then the car faces the other direction. (00:28:45 - 00:29:45)
Continuity mistake: When Tony is giving his address to the Mandarin through the media the reporter in front of him has a cell phone which changes design between shots. (00:28:50)
Continuity mistake: When Tony Stark and Col. Rhodes confront the Mandarin in his chair the hammer for the Beretta is forward after Rhodes loaded a new magazine. The hammer is shown in the back position in a subsequent shot. It happens twice during this scene. (01:30:05)
Continuity mistake: When Tony is sending a holiday greeting to The Mandarin, he has sunglasses on. Then in the shot from behind, he doesn't have any glasses on. Then they reappear in the next shot and then he takes off the sunglasses. (00:28:55)
Continuity mistake: When Tony is in his garage injecting his arm, his chest piece is glowing brightly through his shirt, however, the very next shot when he is wiping his arm with the alcohol pad, his chest piece is suddenly turned off. (00:05:15)
Continuity mistake: When Tony is working on the laptop in the van, the IP address shows as 934.554.32.3. Not only is that an invalid address, but when he enters Rhodes' credentials, the IP changes to 93.455.43.232 (also invalid). (01:05:45)
Continuity mistake: When Stark gets trapped by the water tank he is completely soaked. When he walks back to the car with the boy he is completely dry and his hair is restyled with not enough time for this to happen. (00:56:50 - 00:57:55)
Continuity mistake: When Tony and Rhodes leave the Mandarin's mansion, Tony has blood on his left eye and cheek, which changes to the other eye between shots, then changes again at the boat. (01:30:25)
Continuity mistake: When Tony is creating his weapons, one shot shows the electric glove he is wearing to be designed for his left hand. Later on, when he is in the Mandarin's mansion, he attacks one of the guards with the electric glove, only now the glove is on his right hand. (01:12:50 - 01:14:10)
Continuity mistake: Tony is in the bedroom with Maya Hansen, Happy is seen closing the sliding door. With the door just inches from being fully closed, a quick cut to Tony and Maya kissing, then back to Happy, and the door is almost fully open, with Happy in the process of closing it again just as the plant explodes. (00:03:45)
Continuity mistake: When Jarvis wakes Tony up when he is in Tennessee, there is quite a lot of blood on his face. But when he takes off his mask, so before he had any time to wipe it off, the amount of blood decreases significantly. (00:39:50 - 00:40:30)
Continuity mistake: When Tony is talking with Rhodes at the bar, his chest is not glowing.
Continuity mistake: When Tony and Pepper are attacked by 3 missile-wielding helicopters, Tony, dressed in his metallic suit, has blood on his nose and cheeks. Problem is: The blood increases on his face, which is normal as it is still bleeding, but then it lessens. Then it gets worse again. (00:37:45 - 00:38:45)
Continuity mistake: Colonel Rhodes holds his pistol to the face of the Mandarin in a close up shot, then lowers it. The next instant shot later of Rhodes show him still holding the pistol to the Mandarin's face.
Continuity mistake: When the Mark 42 is "done" assembling for the first time, in Tony's workshop, a digital model of the suit appears in the lower right corner of the screen. In this render, the suit is complete, but a moment later there is still one piece missing, which hits Tony so hard the entire suit falls apart. (00:07:30)
Continuity mistake: When Tony leaves the bar, his hands are cuffed behind his back. When he is shot at in the next scene after jumping through the window, his hands are somehow cuffed in the front of his body. (01:54:50)
Continuity mistake: When Tony is attacked by helicopters in his Malibu mansion, his right hand has a black wrap around it. After he gets buried by rubble underwater in the suit, his right armored hand detaches and grabs his bare right hand to pull Tony out from the rubble. Tony's bare hand no longer has a black wrap.
Continuity mistake: As the house is being attacked, Tony slides down the floor, smashes through a window and grabs onto the window frame. As the shot ends, his head is definitely under the frame, but in the instant shot following, his head is suddenly over the window frame. (00:36:00)
Chosen answer: The Battle of New York was never specified to take place in 2012, we just know that the film came out then. Based on the newspaper we can assume that the battle was in June 2013, rather than some time in 2012 as many would have previously assumed.