The snowfall is like the impact of war on the students because of the insidious way it creeps up on them. Although the boys know that the war is coming, when it finally affects them directly, they hardly notice it. Similarly, they know that winter is coming and that with winter will come the snow, but when the change in seasons finally arrives, it is so gradual that it creates no shock at all. About this analogy, Gene says,
"Devon was...very close to the ways of peace...the war was...no more taxing to us than a day spent at harvesting in an apple orchard...Not long afterward...snow came...like noiseless invaders conquering because they took possession so gently...In the same way the war, beginning almost humorously with announcements about maids and days spent at apple-picking, commenced its invasion of the school. The early snow was commandeered as its advance guard."
Another analogy that might be used to compare nature and war that comes to mind is fog, which also creeps slowly and quietly, until it envelops everything, having come almost unnoticed.
The mood of the Summer Session is relaxed, laid back, almost idyllic. In contrast, the Fall Session is intense, busy, and ordered. Some reasons for these differences is that in the summer, the younger students such as Gene and Finny are allowed a great deal of freedom. While the focus at Devon is on the seniors, who are "practically soldiers," the younger boys, for whom the concept of war remains in the distance, are largely left alone, allowed to enjoy their waning days of childhood. The staff is also at a minimum during the summer; there is not a lot of adult supervision or structure, unlike in the fall. In addition, the Summer Session is newly established, and does not have the decades of tradition and order behind it, as does the Fall Session.