Nocturnalromantic is a term for those who feel that their romantic attraction is stronger at night and weakens at daytime or simply doesn't exist during daytime.
One who is nocturnalromantic may or not feel that their romantic attraction increases when simply thinking about the night or playing a game in which it's nighttime, as an example.
The opposite is diurnalromantic.
The sexual counterpart is nocturnalsexual, the platonic counterpart is nocturnalpla.
History
This term was coined on 7 April, 2021 by FANDOM user Friendly Clown Boy.
Flag
The flag was designed by FANDOM user Reign of the breadsticcs on April 10, 2021. It represents romantic attraction being weaker or nonexistent during the day (the thinner, lighter blue stripes), and it increasing as nighttime arrives (thicker, darker blue stripes).
Resources
https://withers-coining.tumblr.com/post/669723098255376384/nocturnalromamtic