That time of the year when the temperature drops and snow falls. Also a time of great trial for yukkuris due to their intolerance to cold temperatures.
Wild yukkuris will need to have had collected a food stockpile during autumn to hibernate through winter. A single mistake (such as making children which greatly increases food requirement) can lead to the demise of an entire family or even an entire clan.
City strays have it worse. Their main food source, garbage, can't be stored like a wild yukkuri's nuts and berries. In addition their cardboard homes aren't as coldproof as a wild yu's cave. Because of this, city strays generally have adapted to be able to tolerate cold better, but in exchange they'll have to bear the cold and go dumpster diving every day throughout winter.