One of the outstanding details in Harper Lee's To Kill a Mockingbird that reveal the setting, found in Chapter Eight, is the snowfall.
Next morning I awoke, looked out the window and nearly died of fright. My screams brought Atticus from his bathroom half-shaven.
"The world's endin', Atticus! Please so something—!" I dragged him to the window and pointed.
"No it's not," he said. "It's snowing."
This scene is indicative of the southern setting of the novel: in Alabama, Scout has never seen snow in all of her life. Neither has Jem. Eula May, "Maycomb's leading operator," calls, as Atticus says, to announce:
And I quote—'It has not snowed in Maycomb County since 1885, there will be no school today.'
Of the light snow that does fall, Jem and Scout do their best to make a snowman (borrowing some of Miss Maudie's snow from her yard), which ends up being a little part snow and a larger part mud. It is quite an accomplishment when they are finished and Scout tells Jem it is "lovely." She is sure it looks real enough to talk. Jem, shyly embarrassed and yet pleased, agrees. However, Atticus quickly notes that while it is a masterpiece (which makes Jem again proud but embarrassed), it looks too much like their neighbor Mr. Avery. Atticus has the children dress the figure up to change its appearance so Mr. Avery is not offended by their "caricature."
The second detail that takes on significance with regard to the story's setting is the temperature. Before Scout goes to sleep that night, Atticus tries to warm her room up:
...Atticus put more coal on the fire in my room. He said the thermometer registered sixteen, that it was the coldest night in his memory, and that our snowman outside was frozen solid.
Atticus is not as ancient as the children believe, but he did have children later in life than most of Jem and Scout's friends (and they think he is "feeble" for it), something that comes into question when he surprises his children with what an excellent marksman he is in Chapter Ten in his encounter with Tim Johnson (simply out of necessity, for Atticus is never one to brag). We learn Atticus is fifty (as Miss Maudie mentions in the same chapter), and that it has been at least the length of Atticus' life since it has been so cold, for it has not happened before as best as he can remember. This sudden drop in temperature is another detail that provides the reader with information about the story's setting, as presented in Chapter Eight.