Traditionally, you should put your Christmas tree up on Christmas Eve:
https://en.wikipedia.org/wiki/Christmas_tree#Setting_up_and_taking_down
'When I were but a nipper' my mother would be furious if she saw that people had put their Christmas trees up before then, denigrating them with the most vicious word in her armoury: "Common!"
Our local church (where you might think that they'd know a thing or two about Christmas) has already got it's illuminated tree outside but otherwise the timeline seems to be as follows:
Before mid-November: Stores and shopping centres only.
Mid-November: Essex girls and chavs, plus pubs with regular karaoke nights and giant Sky Sports screens. (Or, as my mother would have described all of them, "Common, the whole lot of them!")
End of November/Beginning of December: Most other pubs, plus families with young children.
Mid-December: Most other households.
Christmas Eve: The 'county set' and a few other staunch traditionalists.
Boxing Day: Me! (Well that's when I usually get around to putting my tiny plastic tree, with its battery-powered fibre optic lights, onto my desk anyway)
;-)