Harper Lee does not directly tell the reader what years the novel takes place during. What are some clues that she provides to help the reader determine the time period?

Actually, although Lee does not provide the exact years, she does specifically talk about the Great Depression.

It’s never entered that wool of hers that the only reason I keep her is because this depression’s on and she needs her dollar and a
quarter every week she can get it.”

There was no hurry, for there was nowhere to go, nothing to buy and no money to buy it with, nothing to see outside the boundaries
of Maycomb County.

The question and answer are both erroneous.

Though it is true that Lee does not offer a specific year for the start of the story in To Kill a Mockingbird, Atticus's summation to the jury at the trial of Tom Robinson includes the comment that "'There is a tendency in this year of grace, 1935, for certain people to use this phrase out of context, to satisfy all conditions'" (Lee 233-34). This clearly indicates that the one day trial of Robinson takes place in the summer of 1935. It is summer because Dill had not appeared that summer as he had the two summers previously, but then shows up after running away, so he is in attendance at the trial with Scout and Jem. The story starts with the summer that Dill first arrives in Maycomb when Scout is "...almost six and Jem was nearly ten" (6), and it ends the night Jem's arm is broken "When he was nearly thirteen, my brother Jem got his arm badly broken at the elbow" (3).

Through the use of deduction and astute observation of time references while reading the novel, one should be able to discern that the novel starts in the summer of 1933 and ends in October 1935. It is difficult to be more exact than this because neither Jem's nor Scout's birthdays are given by Lee. The closest we get is that Jem and Scout are heading to town on a Saturday during the school year to spend Jem's twelfth birthday money when they have the encounter with Mrs. Dubose. Jem's explosive reaction to Mrs. Dubose's less-than-complimentary comment about Atticus on the way home from the store includes the destruction of camellias, a plant that commonly blooms in "winter" in the southern U.S. Jem's destructive outburst results in his having to read to Mrs. Dubose for one month. After one month, his disciplinary sentence ends and the very next sentence has Scout reporting "That spring was a good one:" (126). It is another month after that when Mrs. Dubose passes away just before Part Two of the novel begins, and Scout reports that Jem is twelve and is acting peculiarly. Upon her death, Mrs. Dubose bequeaths a camellia blossom to Jem as a reminder of his ineffective attempt to kill the camellias. If one notes that Jem is allegedly nearly thirteen when he accompanies Scout home after the Halloween school pageant, and yet, earlier he and Scout go to town to spend his birthday money a month or two before Scout mentions spring, then the reader is left with only that Jem's birthday occurs sometime between November and perhaps February, which is quite a span of time. Regardless, Dill shows up at the beginning of the novel during the summer, the trial occurs in the summer of 1935, and the end of the novel is Halloween a few months after the trial.