Quote Originally Posted by maxmixiv View Post
Боб, haven't you noticed, that phrase "в четыре утра" could be heard more often than "в четыре ночи"?
And it is very unlikely to encounter "в пять часов ночи"?
I agree, of course, that there is no clear boundary.
Hmm... Nope, I usually hear "в четыре ночи", at least among my friends. I'm a night owl by myself, I'm used to falling asleep late (after 2:00), and waking up late, too Since I have to work with companies in the US. Maybe that explains why

Yes, I did hear some people saying "в четыре утра", but that's a bit strange for me.
However, it's not a reason for arguing. I agree opinions may differ.