Just to further MT's great explanation, a modern version might be something like ..
- What the heck hour of the night is it anyway?
- hmm, just now it look's like there's an argument going on between night and the sunrise...
An interesting question for me with a line like this, is W.S. really "getting at" some other meaning, and then perhaps, an even deeper meaning?
The lines (just on their own - twelve words - no further elements from the astounding work of art needed) certainly make me think of the distinction between good/bad, positive/negative, yin/yang...
I'm immediately put in to a somewhat spooky place where you don't quite know what's going on, and you - Macbeth - everyone - is internally mixed-up about just what is good and bad, what is reality and dream .. what is life and what is a story ... it's pretty potent stuff.
(There's a cheesy line from a pop song "Does anybody really know what time it is?" ... it's the same sort of thing diluted a hundred times.)