Based on our testing, each instance of day lasts about 16 minutes and night lasts about 8 minutes, if you're just standing around, doing nothing. (In other words, one IRL minute kind of equals one in-game hour.
So total 1 minute irl is about an hour in the game.
This time is paused for in-game events like cutscenes and battles though
Source: https://www.polygon.com/pokemon-legends-z-a-plza-time-change-day-night-length
