Apple in macOS Mojave introduced Dynamic Desktops, which are wallpapers that shift with the time of day, changing the lighting and look of the wallpaper with the progress of the sun across the sky.

For example, in the afternoon, the lighting in the wallpaper is at its peak brightness and the image of the Mojave desert is depicted as it would be if you visited it in the daytime with well-lit sand dunes and a bright blue sky.

Dynamic Desktop is simple to enable. Here's how:

1. Open up System Preferences.
2. Choose Desktop & Screensaver.
3. Select one of the options from the "Dynamic Desktop" section under "Desktop."
4. Using the dropdown menu underneath the wallpaper's name, make sure "Dynamic" is enabled.

There are two Dynamic Desktop options in macOS Mojave, which work with both Light and Dark Mode.

You can choose between the wallpaper that depicts the Mojave desert and a Solar Gradients wallpaper that shifts from a lighter sky blue in the daytime to a darker twilight blue. Apple is likely to add additional Dynamic Desktop options in the future.

Apple's Dynamic Desktop feature relies on your location to be able to match the lighting of the wallpaper with the lighting outside, so to use it, you will need to have Location Services enabled.