Dolphin clock off on time

[JosJuice]

I don't know exactly how it works, but maybe the clock slows down when the game isn't running at 100% speed? If so, I don't think there's much you can do other than restarting occasionally to get the right time or hoping that Dolphin won't lag. Luckily, Animal Crossing is very lightweight, so it will run better than Zelda: Twilight Princess.