The novel "Fahrenheit 451" takes place in the future and there are a few examples through the first couple of pages that demonstrate that it takes place in the future.
On page 4 it states, "He walked out of the fire station and along the midnight street toward the subway where the silent air-propelled train slid soundlessly down its lubriacted flue in the earth and let him out with a great puff of warm air onto the cream-tiled escalator rising to the suburb."
On page 5 we learn that the novel takes place in the fall or autumn: The autumn leaves blew over the moonlit pavement in sucah a way as to the make the girl..."
On page 18 after Mildred tries to committ suicide is a description of what they use to make breakfast in the morning: "Toast popped out of the silver taster, was seized by a spidery metal hand that drenched it with melted butter."
All of these passages are evidence that this story takes place in the future because we do not have these kinds of luxuries in our society today.