What explanation does Mr. Avery offer for the cold winter?
This question relates to the gossip and superstitions of the citizens in Maycomb (both children and adults) and the children (Jem, Dill, and Scout) often annoying or upsetting adults in their neighborhood such as Mr. Avery, Arthur(Boo) Radley, and Mrs. Dubose.
Mr. Avery is a minor character and neighbor of Jem and Scout in To Kill a Mockingbird. Avery's explanation for the cold winter is that weather change is a result of the children's poor behavior, for example, disobeying their parents.
Previously, Jem and Scout have disobeyed their father, Atticus Finch, by acting out the gossip about Arthur (Boo) Radley using a pair of scissors to stab his own father in the leg. Atticus caught them acting out this scene, warned the children to leave Boo Radley alone, and takes the scissors away. Jem and Dill still want to act out scenes about the Radleys while Scout starts feeling guilty.
Her father's warnings later scare Scout when Mr. Avery connects children's sins and the cold change in weather. Scout believes the children's acting was a sin and has caused snow as a result of their sin.
The children's actions are not actually as serious as Mr. Avery says, but Scout is convinced because she is a young child who still relies on the beliefs of the adults.
Although it's a minor event in the story, it touches upon key ideas woven throughout the novel such as gossip, superstitions, and the nature of sinning (a key element in understanding the novel and the title).