With the release of macOS 10.12.4, Mac users gained the ability to take advantage of Night Shift, which adjusts the Mac display to a warmer color in the evening hours, which can help reduce eye strain and help sleeping patterns.
The option has been available to iOS users for awhile, and the effect was previously only available to Mac users who downloaded the Flux utility, (which is still a great option for Mac OS X users who don’t plan on upgrading to macOS).
With Night Shift enabled, when the sun goes down, or at the custom time that you set, the display temperature of the display will change to become warmer automatically. The display warmth will be reduced automatically at sunrise, or at a custom time chosen by you.
For more tips and tricks on how to make better use of your Mac, iOS device, Apple Watch, or Apple TV, be sure to visit the “How To” section of our website.
(Thanks for the original tip go to OSXDaily.com)