Did the events of 55 minutes light novel actually happen in the summer?

I haven't read this novel completely yet, but it was said in the afterwords of the novel that for some reason the events of this novel happened in the summer. I want to know if it stays like this until the end of the novel and the events of this novel really take place in the summer? Or at the end, a plot twist occurs and it turns out that the events of this novel are not known in which season they happened, and an ability user just manipulated the season so that it seems like it is summer?