Toggle light and dark themes

This technique for running apps or opening files at a certain time of the day using Calendar events can be used for many other purposes.

1 Create an app

Open Automator and in the file selection window that appears. Click ‘New Document’. When it prompts you to choose a type, select ‘Application’. We will create and save an app.

2 Add an action

Click the ‘Library’ button if the library is not visible and then click and drag ‘Change System Appearance’ from the actions list and drop it on the right side of the window.

3 Test the app

This action switches light and dark modes. Click ‘Run’ in the top-right corner to test it. There is an option to select light or dark mode, but leave it as ‘Toggle Light/dark’.

4 Save the app

Save this Automator action as an app to the disk and set the file format to ‘Application’. Any folder will do – we created an Automator subfolder in the Documents folder.

5 Create an event

Open Calendar. It is useful to create a new calendar for Automator events, but it is not essential. Double-click on ‘Today’ to create a new event and then name it ‘Dark Mode’.

6 Repeat daily

Set the time of the event to the time at which you want to switch macos theme to Dark Mode, such as 5pm. Click the ‘Repeat’ option and set the event to occur every day.

7 Custom alert

Calendar events are normally created to remind you of appointments, but what we want to do is run our Toggle Dark Mode app. Click ‘Alert’ and select ‘Custom’ from the menu.

8 Run an app

In the panel that appears set the alert to ‘Open File’ in the top item. In the second item select the option to ‘Open File’ and choose the Toggle Dark Mode app we saved.

9 Create another event

The event is done and at 5pm each day dark/light mode is toggled and macos goes dark. Repeat these steps to create an event in the morning to toggle it back to Light Mode.