NightOwl will toggle the Dark/Light Modes based on your chosen time. You only have to set it up once, then it will run in the background.
Want your Mac to be in Dark Mode during night and switched back to Light Mode, when the sun rises? NightOwl does the work for you.
It only takes you a second to switch between Mojaves Dark/Light Modes by using the Hotkeys. Press, "Huuhuuhhh", dark. - that easy