How to change screen brightness based on time of day on Windows 10

Screen brightness is a basic control on any display. You can change it to whatever suits you or if you have the hardware for it, you can use adaptive brightness. Adaptive brightness is fairly common and is found on desktops and mobiles alike. It changes the brightness of the screen based on the ambient light. It’s useful but you must have hardware that supports it. If you want to change screen brightness based on time of day though, you’ll find there aren’t a lot of options out there. Most apps that claim to do this are not reliable but ClickMonitorDDC is the rare exception.

This article deals with screen brightness and not the temperature of the screen. For some reason, most app developers equate screen brightness with screen temperature when they are distinctively different. If you’re looking to change the screen temperature based on time of day, use Night Light on Windows 10, or use the F.lux app.

Change screen brightness based on time of day

Download and run ClickMonitorDDC. The app runs in the system tray. Open it and click the button at the top left of the panel that appears. In the new settings window that opens, go to the Timer, Transfer, Limits tab.

On the Time, Transfer, Limits tab, you will see a section called ‘auto-run command-lines’, it has support for eight different time triggers that we’re going to use to change the screen brightness. You also have the option to change the contrast and luminance but you can leave it out if you want.

First, set the time when the brightness should change. Next, enter the letter ‘b’ and follow it up with the brightness level you want to set at that time. For contrast, add a space after the first command and enter ‘c’, follow it up with the contrast value you want to set. Finally, if you want to set luminance, enter an ‘l’ and its level. This will set the blue luminance level.

Sample settings

b20 c50 l200 b10 c40 b25

Add as many time triggers as you need and the app will allow. Click Apply and OK. The app will change the screen brightness for all your displays. If for some reason the app doesn’t change the brightness on one of your displays, you can use this very same app to sync brightness between them.

There is really only one limitation to this method; it will only work on external displays that support the DDC-protocol. It will work for all laptop displays though you may not be able to set the contrast level for an internal display.