The tone of “The Lottery” is calm and matter-of-fact. This comes across from the beginning of the story, as the narrator describes the children starting to gather ahead of the lottery:
The children assembled first, of course. School was recently over for the summer, and the feeling of liberty sat uneasily on most of them; they tended to gather together quietly for a while before they broke into boisterous play and their talk was still of the classroom and the teacher, of books and reprimands.
The narrator’s matter-of-fact tone comes across in the way that they note how "of course" the children are the first to gather in the square. This narrator is clearly familiar with the goings-on of this community, and is possibly even a member of the community themselves. The narrator goes on to calmly describe how the children “gathered quietly,” “broke into boisterous play,” and also spoke of everyday topics like “books and reprimands.”
It is notable that, in this passage, as in many others, the narrator subtly alludes to an underlying anxiety, such as in the description of how “liberty sat uneasily” on the children. While, on the surface, the narrator is referring to the way that the children are having trouble transitioning from the structure of the school year to the freedom of summer vacation, it is possible to read this as a commentary on the way the community itself is uncomfortable with freedom, as seen in the fact that they refuse to stop holding the annual lottery and killing a member of their community for no clear reason. This juxtaposition of the narrator’s calm tone and the subtle allusions to the community’s collective unease contributes to the unsettling mood in the story.