If you are working with code based deployments instead of using CMS to push out changes, you might have already implemented something similar.

There are 2 approches to implementing this:

1) Define and save date formats

function mymodule_custom_date() {
$date_format_monthday = 'm-d';
 
$format = array();
$format['format'] = $date_format_monthday;
$format['type'] = 'custom';
$format['locked'] = 0;
$format['is_new'] = 1;
date_format_save($format);
 
$format_type = array();
$format_type['title'] = 'month_day';

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