When Does "The Truman Show" (1998) Take Place?

"The Truman Show" is a science fiction film written by Andrew Niccol that released June 5th, 1998. So when is "The Truman Show" set? 

It takes place roughly in the years: 

1999 AD or 2000s AD 

We know this because a magazine cover dated for something-"999" is shown as part of a video montage so we know it is currently during or after 1999 AD because the technology and fashions on display do not reference the real-world technology or fashions of a different millennium like 999 AD or 2999 AD. 

If the show within the movie has been continuous since Truman Burbank's birth, as claimed later when a newscast says "1.7 billion were there for his birth" and "now in its 30th great year" and the magazine dated for 1999 AD contains an article about it (which it certainly must because why else would it be featured in the montage), therefore the show was airing in 1999 AD and has been on air for 30 years. 

1999 + 30 = 2029. 

Furthermore, two of Truman's fans we see are security guards and a barely visible piece of paper in their little office labeled "LUNCH SPECIALS" also says "3-27-97" for March 27th, 1997 AD directly below. So it is possibly as late as 2029 AD and this menu has been left up for 32 years. Most likely, it is sometime between 1999 AD and 2005 AD, the menu has been forgotten for 7 years, and "The Truman Show" started in this universe at some point like 1975 AD. 

Additionally, the town of Seahaven has a local newspaper "The Island Times" and two issues' front pages can be seen during the story. Both papers and the two magazine covers within the dome are dated for 1996 AD. 

The timeline of the film is fairly unique because the main character within its fictional world (diegesis) does not himself know what year it truly is for the duration of the story. This timeframe clearly refers only to time for Truman who accepts the false narrative they are presented: that it is still 1996 AD in Seahaven. 

This StackExchange user's post examines its exact setting.