Holden's story takes place over only three days, from Saturday afternoon to Monday around 1pm. (It only feels longer.) For the exact year, you have to check out Chapter Five when Holden's talking about Allie's baseball mitt. He says Allie died on July 18, 1946 when Allie was eleven and Holden was thirteen. Back in Chapter Two, Holden mentioned that he's seventeen now (as he's telling us the story) and was sixteen "last year around Christmas" when he left Pencey and bummed around the city for a while.
Ergo, the year of the December New York City escapades is either 1948 or 1949, depending on (1) when Holden's birthday falls and (2) what the exact date is of his story-telling. It follows that the year of seventeen-year-old Holden telling us his story is either 1949 or 1950.
What's the significance of 1948/1949/1950? Just ask the Greatest Generation. The late 1940s puts us smack in the post-World War II era, with Holden as a product of the war: he talks about the war (and the effect it's had on his brother D.B.) with a slightly detached air, mentions the Atomic bomb (which the U.S. busted out in August of 1945), and—just possibly—stands for a sort of post-war and post-bomb nation-wide "loss of innocence."
In other words, Holden’s language isn’t the novel’s only historically specific element. His general feelings of isolation and disillusionment are also tied to a particular time and place—like the growing conformity and consumerism of post-War America. So here’s our question: is Holden a hero for all time? Are his teenage issues the same issues rich (and poor) teens face today? Or is this novel already hopelessly dated?
And then there’s geography. We go from Pencey Prep—land of the phonies—to New York City, land of the … phonies. Once we’re in New York, we go from bar to bar, hotel to hotel, and park to park. Holden thinks that by switching location, he can escape the people and attitudes he dislikes.