When Does the Film "Iron Man 2" (2010) Take Place?

"Iron Man 2" is a superhero film written by Justin Theroux [adapted mostly from the comic-books "Iron Man" #223-#225 (1987) by David Michelinie with Bob Layton as well as "The Invincible Iron Man" #169 (1983) by Dennis O'Neil] and released in a public theater on April 26th, 2010. (Wide release was May 7th, 2010.) 

It takes place on the fictional Marvel Cinematic Universe timeline in the year: 

2011 AD 

We know this because of various references to "Thor" (2011) and "The Incredible Hulk" (2008). Plus a single line of dialogue in “The Avengers” (2012). 

For the film to be concurrent with "The Incredible Hulk" (2008) (as hinted at by the appearance of news footage of the events of that film during the two-part epilogue) and for it to be concurrent with "Thor" (2011) (as very clearly stated by S.H.I.E.L.D. Director Nicholas Fury in the donut shop scene ["I have bigger problems than you in the southwest region to deal with"] and Agent Phil Coulson later ["Director Fury wants me in New Mexico"]) it must take place in 2011 AD. 

Furthermore, Natasha Romanoff's fake résumé includes a date for her planned graduation from Harvard Law School ("Candidate for J.D.") in "June 2010". More importantly, it includes a date for starting work in the legal department at "Stark Industries" as a "Legal Assistant" that reads "2010-Present". She is referred to in the same scene as "from Legal" so we know that this fake information is supposed to be current to her most recent job move (especially as it includes a Stark Industries e-mail address). All for her cover story. Therefore, the main action of the film has to take place in or (most likely) after 2010 AD. 

Additionally, the film opens with a prologue including a montage that ends in a title card that reads "6 months later". This title card was mistakenly understood among fans for some time to retroactively establish when the previous film, “Iron Man” (2008) takes place because the prologue starts simultaneous with the end of the previous film (which takes place in 2008 AD) but the following montage clearly show a long and arduous progression of scientific experimentation and electrical engineering over an unspecified period of time. Therefore, we must work backward from the rest of the film. The film’s prologue starts in 2008 AD and ends 6 months before the main action of the film, which places that either in early 2011 AD or mid-2010 AD. 

Finally, the film ends with two epilogues. The first includes the news footage covering events from "The Incredible Hulk" (2008) and a screen may be showing a crater created during the events of "Thor" (2011). 

The second is implied to be soon after the main action of the film but is unplaceable. 

There is also an end-credits scene which must take place midway through "Thor" (2011). 

This Geekritique article and video examines its exact setting. 

It is a chronologically early film in the Marvel Cinematic Universe.