In the morning it returns the display to its regular settings. It then automatically shifts the colors in your display to the warmer end of the spectrum.
Night Shift uses your computer's clock and geolocation to determine when it's sunset in your location. Studies have shown that exposure to bright blue light in the evening can affect your circadian rhythms and make it harder to fall asleep. Night Shift automatically shifts the colors of your display to the warmer end of the color spectrum after dark.
