It has been reported on Reddit, that communities in Fallout 4 are prone to celebrating seasonal events. Discovered first in Diamond City, players of the game said that they have come across its population celebrating Christmas, and commenting on it too.
Before you ask why Sanctuary features Halloween decorations all the time however, be aware that the Great War, according to Fallout lore, started at the tail end of October, 2077. These will remain persistent. However, go to Diamond City during the in-game Christmas period, and be greeted by lights and Christmas trees.
To find out what date it is in your game of Fallout 4, bring up your Pipboy and go to the map screen. In the bottom left corner, you should see the exact date. We imagine a few more date-related events are littered in the game’s world, and it won’t be long before some PC fans mod the clock and do some investigating.