Nocturnalsexual is a term for those who feel that their sexual attraction is stronger at night and weakens at daytime, or simply doesn't exist during daytime.
One who is nocturnalsexual may or may not feel that their sexual attraction increases when simply thinking about the night or playing a game in which it's nighttime, as an example.
The opposite is diurnalsexual.
The romantic counterpart is nocturnalromantic, the platonic counterpart is nocturnalpla.
History
The term was coined by FANDOM user NyxIsSus on July 31, 2021, after discovering that nocturnalromantic did not have a sexual counterpart.