Custom archive widget drop down menu

The archives widget uses the wp_get_archives function to generate the dropdown list. As you can see from the source code, there is no native way to use other dropdowns than yearly/monthly/weekly/daily. Unfortunately, there also is no hook to insert your own quarterly dropdown. So, there is no easy way to do this.

There is a deeper problem, too: there is no native WP way to link to a bunch of posts by quarter as there is for years and months. This exists: www.example.com\2017\05. This doesn’t: www.example.com\2017\Q1.

That doesn’t mean it can’t be done. But you’re looking at building your own archive dropdown widget and combining it with a smart date query to be able to link to a quarterly archive.