When Does the Film "Thor" (2011) Take Place?
"Thor" is a fantasy superhero film written by Ashley Edward Miller with J. Michael Straczynski, Zack Stentz, Don Payne, Mark Protosevich, and Matthew Vaughn [adapting "Journey Into Mystery" #85 (1962) as well as “The Mighty Thor” #145 (1967), both by Stan Lee] and released April 21st, 2011.
We know this because of a single line of dialogue in “The Avengers” (2012). In that film, S.H.I.E.L.D. Director Nicholas Fury says, "Last year, Earth had a visitor from another planet who had a grudge match that leveled a small town", referring to Loki and the events of this film, after pointing at Thor. "The Avengers" (2012) takes place entirely in 2012 AD.
It takes place on the fictional Marvel Cinematic Universe timeline in the year:
2011 AD
We know this because of a single line of dialogue in “The Avengers” (2012). In that film, S.H.I.E.L.D. Director Nicholas Fury says, "Last year, Earth had a visitor from another planet who had a grudge match that leveled a small town", referring to Loki and the events of this film, after pointing at Thor. "The Avengers" (2012) takes place entirely in 2012 AD.
2012 - 1 = 2011.
Additionally, there is a prologue that clearly takes place in 965 AD, as it's labeled with a place and time setting title card reading: "TONSBERG, NORWAY 965 A.D." over the footage.
This Geekritique article and video examines its exact setting.
It is a chronologically early film in the Marvel Cinematic Universe (a first chronological film to feature Thor) and can be watched either at its timeline point or entirely separately.