Just call it "evening" if it's before midnight. That way you get four nicely subdivided periods.
00-06 - night
06-12 - morning
12-18 - afternoon
18-24 - evening
Would need to refactor the name of "midnight" tho to minimize confusion. But if we use it as a starting point to count hours in a day from, it doesn't make sense to simultaneously designate it as a middle of anything.
(BTW, such subdivision is actually common in many places of the world.)
00-06 - night
06-12 - morning
12-18 - afternoon
18-24 - evening
Would need to refactor the name of "midnight" tho to minimize confusion. But if we use it as a starting point to count hours in a day from, it doesn't make sense to simultaneously designate it as a middle of anything.
(BTW, such subdivision is actually common in many places of the world.)