The assassination sequence portrays, as a number of films do, live TV pictures of the motorcade. There was no live TV coverage and much the footage shown in the film as "live" was first broadcast on the evening of November 22, 1963 as it had been filmed earlier that day.
A title card tells us it's 1962. A few scenes later, Ruby watches Joe Valachi on TV testifying about the Mafia before Senator John L. McClellan's Permanent Subcommittee on Investigations. The hearings took place in September, 1963.
The opening scene with Candy Cane is set in 1962 but behind her on the TV is a speech by JFK. It's JFK's New Frontier speech which was delivered two years earlier at the 1960 Democratic National Convention.