When Does the Film "Superman III" (1983) Take Place?
"Superman III" is a comedy superhero film written by David Newman with Leslie Newman [adapting the Superboy story in "Adventure Comics" #255 (1958) by Otto Binder as well as "Superman" #317 v1 (1977) by Marty Pasko] and released June 17th, 1983.
We know this because a banner visible outside his Smallville High School reunion party establishes that Clark Kent graduated high school as part of the “Class of 1965”. Though it’s not stated what year of duration a reunion it is there would only be 2 reunions between the events of the previous film, "Superman II" (1980), which takes place in 1978 AD or 1979 AD (depending on the cut), and the events of the next film "Superman IV: The Quest for Peace" (1987), which takes place in 1985 AD (and has one small reference to this film).
It takes place on an alternate timeline of the fictional DC Films Universe in the year:
1980 AD
We know this because a banner visible outside his Smallville High School reunion party establishes that Clark Kent graduated high school as part of the “Class of 1965”. Though it’s not stated what year of duration a reunion it is there would only be 2 reunions between the events of the previous film, "Superman II" (1980), which takes place in 1978 AD or 1979 AD (depending on the cut), and the events of the next film "Superman IV: The Quest for Peace" (1987), which takes place in 1985 AD (and has one small reference to this film).
1965 + 15 = 1980
or
1965 + 20 = 1985.
A traditional Olympic Torch flame is featured in one later scene and these monumental ceremonial fires are only seen once every 4 years during an Olympic Games competition. There were Olympics Games in 1980 AD (both Summer Games and Winter Games) but NOT in 1985 AD. Therefore, the current year is 1980 AD.
It is a chronologically early film in the DC Films timeline (a third chronological film to feature Kal-El/Clark Kent/Superman) and can be watched at its timeline point.
It was adapted to prose in late 1983.