Samsung
Night Mode: Set a Schedule auf Samsung
Night mode dims the display and switches the interface to darker tones, but on a fresh setup it usually only reacts when you toggle it by hand.
The schedule option sits inside the same menu as the night mode switch itself. To reach it, go to Open the Settings ➔ Tap on Display ➔ Tap on Night mode ➔ Enable or disable Turn on as scheduled.
Once that toggle is on, you get two ways to run the schedule. You can set a fixed start and end time yourself, which is useful if you keep regular hours and want night mode active during the same window every day.
Alternatively, you can let the schedule follow sunset and sunrise. In that mode, the system checks your location and time zone to turn night mode on when it gets dark and off again in the morning, so the timing shifts with the seasons instead of staying fixed.
If night mode still does not switch automatically after setting the schedule, check that location access is allowed when you use the sunset-to-sunrise option, since the calculation depends on it.
A fixed-time schedule works independently of location and is the more predictable choice if you travel often or disable location services.