If you are an avid Shortcuts user, there is a good chance you would want to automate certain things to run quarterly, or semiannually, or perhaps only on specific months of the year — a feature current version of Shortcuts does not have. But a shortcut can be automated to run every month. In other words, if you have a subroutine shortcut, it is possible to selectively run on specific months.

1. Download the shortcut through this link.
2. The shortcut takes a Text, such as this:

03, 06, 09, 12

For specific use case, it is possible to simply select all months with ALL.

3. Following example would return True, if it was run on the selected month (e.g. on month of August, it will return True, and in September, False).

06, 07, 08

It can be implemented in many different ways as it is designed to be used as a subroutine. The scenario I described above would go like this:

1. You have a shortcut that needs to run quarterly (Mar, Jun, Sep, Dec). Set it to run every month on Shortcuts app.
2. Add “Run Shortcut” and select “Current Month Match” with 03, 06, 09, 12 in Text passed as input. If the “Run Shortcut” action returns False, stop the shortcut.
   

It’s a simple implementation, and you now have a shortcut that is running quarterly.

If you are interested in making the same shortcut yourself, — instead of downloading it from the link — the principle behind it is also plain. It takes a Text filled with months then run a match action against the current month that is formatted into two digit. It’s a great way to automate that happens less frequently than what iOS seems to anticipate — daily, weekly, monthly.