The Winterval Tradition
Snow is a difficult environment for monsters to spawn in because it dampens everything. In the days before guardians, during the Blackout War, snow days around the end of the year were times when children and adults could emerge from bunkers without fear; When there were silent nights and safe times to gather in the city itself. It became a time to celebrate hope and community and this festive atmosphere, combined with the dampening effect of the snow was enough to keep monsters away for eight nights a year.