As a matter of record keeping, you should probably add
- {{delete|This article has no in-universe information, and should be moved to [[{{PAGENAME}} (real world)]], then deleted until such time as in-universe information can be found about this day}}
to pages like 31 January.
Since these articles are in-universe articles, they cannot exist with only a behind the scenes section like 31 January.
By marking with {{delete}}, you'll be creating a list of all the pages that need in-universe information found.