Nightvision & Time
DAY & NIGHT CYCLE
Press Tab to open Character Screen in the upper right corner you will find Asset Location and Time next to it.
Every 1 minute in real life = 6 minutes in-game
Day Starts at 6:00
Night Starts at 18:00
NIGHTVISION
With Update 5.5 comes Nightvision and good news its a stat you can raise up. As long as you keep tabs on your nutrients! Read more about Diet & Nutrients. Below shows different dinosaurs at different levels of diet. To activate nightvision use the X Key (alternate keybind is: Alt + N). Dinosaurs underwater may have a different nightvision appearance than those on the surface.
Moon Cycles
It is assumed the moon goes through different stages the longer you play you may see more of the moon cycles. It is unsure if the moon follows any specific cycle, if its random, or if its just effected by weather such as thunderstorms and that's why night time can be so dark.
More testing needed.