There has been a long and winding way for routines at Google's home and assistant. When the feature went live during March, there were only six routines with limited actions, but on I / O it was promised that customization and planning would come later. Custom routines landed shortly after, in May, but the planning took their sweet time and has just arrived.
As Cody recently discovered in one of its APK teardown expeditions, you can still trigger your own routines with your specific sentences (on which speaker you're nearby) or set them to start automatically on a particular time and day on a preset speaker. The feature is displayed via a change on the server page, and is apparently still limited to only English-English users.
You'll see the option "Set a time and day" when creating a new custom routine or editing (any of your existing ones). As it says, it's not available for Google's own six preset routines (for morning, night, abandon, etc …). It's a bummer. I really like it if my morning routine could start at 7:30 instead of having to create a new one.
You can choose the time, different days and speaker where the routine will trigger automatically. You can not have different times for different days of the week (eg 7am weekends and 10am weekends, for example), but it is possible to get around by making two similar routines.
The real disadvantage of planning is that you still get the full fan of Google response after a scheduled routine starts, so your speaker will announce all it does instead of performing the routine calmly. Perhaps one day we can disable it. Or maybe it can be overcome by setting the speaker volume to 0% as the first action, then to a normal volume as a final action? This needs testing.