That is a very logical way to describe the parts of the night ;) I also love the word 'poimâine' - so much more eloquent than 'the day after tomorrow'.
Then there's "răspoimâine" = the day after the day after tomorrow.
In fact, -3 -2 -1 TODAY +1 +2 +3 is like this:
răsalaltăieri - alaltăieri - ieri - AZI - mâine - poimâine - răspoimâine
In a 24 hours day, the first hours starting from 00:00 are night hours. Then comes the daylight, when we talk about "azi-noapte" meaning the last night in chronological order, which is part of today. Which is not yesterday night (that would be "ieri-noapte"), although it started yesterday in the evening (before 00:00).