Unclear. Either midnight or as soon as last 24 hours contain less than 6 hours of looped time. I've been wondering this as well. I think I remember something being said like "No combination of time-turners could let you fit more than 30 hours into a day" but I don't know if that really helps...
Where is that written? I well remember that no chain of time turners can send information (at least information comprehensible by humans) back more than 6 hours, but that still allows one to add those 6 hours more than once a day, especially with multiple time turners.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 116.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)