In the game My Time at Portia, the workable/playable day ends around 3AM. Unlike similar games with this mechanic like Stardew Valley, there doesn't appear to be any monetary or item cost if you fail to make it back to your bed by 3AM in Portia.
However, I can't tell if there is any other effect to passing out at 3AM that I might be missing. The game also doesn't seem to mention this in detail on any of the loading screens I've seen thus far.