Technically it wouldn’t matter, but of course by posting in a fresh Open Thread you get better visibility.
(So sometimes it is strategic to wait even if the old Open Thread is still “valid”, but already full of comments.)
And you are right about the time zones; although there is no hard rule when exactly the threads appear, “one day later” is a good rule of thumb.
Technically it wouldn’t matter, but of course by posting in a fresh Open Thread you get better visibility.
(So sometimes it is strategic to wait even if the old Open Thread is still “valid”, but already full of comments.)
And you are right about the time zones; although there is no hard rule when exactly the threads appear, “one day later” is a good rule of thumb.