When Does "That '70s Show" Season One (1998) Take Place?
"That '70s Show" season one is a comedy historical fiction television show showran by Mark Brazill with Bonnie and Terry Turner that released August 23rd, 1998. So when is "That '70s Show" season one set?
It takes place in the years:
We know this because, although the episodes are not in exact chronological order, in season 1 episode 1 "That '70s Pilot", the characters watch TV and Eric Forman narrates it (since the sound is broken) "Wow, Marcia! A football in the face! That's gotta hurt!" The infamous "The Brady Bunch" season 4 episode 18 "The Subject Was Noses" (1973) in which Marcia is hit in the nose by an errant football first aired on February 9th, 1973 AD. So it must be after February of 1973 AD.

1976 AD - 1977 AD
We know this because, although the episodes are not in exact chronological order, in season 1 episode 1 "That '70s Pilot", the characters watch TV and Eric Forman narrates it (since the sound is broken) "Wow, Marcia! A football in the face! That's gotta hurt!" The infamous "The Brady Bunch" season 4 episode 18 "The Subject Was Noses" (1973) in which Marcia is hit in the nose by an errant football first aired on February 9th, 1973 AD. So it must be after February of 1973 AD.
In season 1 episode 3 "Streaking", United States of America President Gerald R. Ford makes a re-election campaign stop in Point Place. A character wears a "FORD '76" button. Ford became president in August of 1974 AD and was up for re-election in the 1976 US presidential campaign so it must be after late 1975 AD.
Furthermore, the first episode opens with a series of time setting title cards which read: "May 17, 1976" and "8:47 p.m.". So, presumably, it's May of 1976 AD at the start of the series.
At season 1 episode 12 "The Best Christmas Ever" the characters celebrate Christmas so we know it's December of 1976 AD at this time.
Season 1 episode 20 "A New Hope" (1999) features the characters attending a screening of the film "Star Wars" (1977), which released in theaters on May 25th, 1977 AD. So we know we have crossed into, at least, May of 1977 AD by this point.