In "A Day's Wait," the boy has been preparing himself for death because he has a temperature of 102. He remembers being told that it is impossible to live with a temperature over 44. However, he gained this information in France, where the Celsius scale is used to measure temperature; he has a temperature of 102 degrees Fahrenheit, just under 39 degrees Celsius. His father tells him this and manages to make him understand that "It's like miles and kilometers" immediately before the final paragraph, which is typically laconic:

"Oh," he said. But his gaze at the foot of his bed relaxed slowly. The hold over himself relaxed too, finally, and the next day it was very slack and he cried very easily at little things that were of no importance.

This conveys that the boy has been tense and keyed-up for some time, preparing to face death as stoically as possible. When the tension is released, he relaxes and feels highly emotional, which causes him to cry easily all the next day. The ostensible reasons for his tears are insignificant: he cries because of his relief and a sense of release from intolerable pressure.