Rewatching the series for timelining.
In 1x01, there's immediately a flashback sequence to the last three times Luz was imprisoned. The Romeo and Juliet tryout flashback takes place on July 15th so apparently they finish school a lot later. The second flashback in that sequence takes place shortly after, since there's still a poster on the wall for the tryouts, probably within the same week. July 15th is a Wednesday, so that'd be July 16th or July 17th. There's no evidence for the third flashback, so a random day in July. The main events of this episode also take place in July, as seen on a calendar in the principal's office. Luz's mother says the Inside-the-Box summer camp is over 3 months, but that goes until September which is after "Luz" returns from camp, so I'll assume she misread the pamphlet or something. The rest of the episode takes place in the Demon Realm.
1x02 is established as the day after 1x01.
There is no evidence as to when 1x03 takes place.
1x04 seems to take place on the night of the same day as 1x03, since King talks about wanting to teach Luz about demons if he became her teacher, then 1x04 opens with King teaching Luz about demons. This is further supported by Luz's "banned" poster not being on the wall in this episode, but being on the wall after it.
I'm gonna keep coming back to this, hopefully it'll take a couple weeks max, then I'll start time stamping everything