A good argument can be made for 'Night' being death or bad times. Consider that there is a 'watchman' that keeps the clock which could also stand for the Grim Reaper or the Angel of Death. Frost lost a son and it affected him deeply. Frost is acquainted with the 'night'. He's seen it affect his neighbors, he's seen it happen in the saddest city lane. Night happens everywhere, and while he does not know 'death' or 'night' closely or personally, he is acquainted with it well.
