## C, <strike>35, 34</strike> 27 bytes

    f(n){n/=time(0)/86400%7^3;}

-7 bytes with thanks to @MartinEnder and @Dennis

[Try it online!][1]


  [1]: https://tio.run/##S9ZNT07@/z9NI0@zOk/ftiQzN1XDQFPfwszEwEDVPM7YuvZ/Zl6JQm5iZp6GJlc1lwIQpGloWoMZBUVAuTQNJZfMlDz1EoXkosTiDD0loGTtfwA