Series by Diva.
Every weekday with first week of the month off, alternating with Zookeepers on weekends.
Uploaded at 12:00 EDT / 11:00 EST.
Additional notes
Athough the linked images go to danbooru, the dates refer to when Diva originally uploaded the image on twitter, not necessarily when they got uploaded here.
Occasionally, Little Nuns and Zookepers may swap schedules, if important events in Little Nuns (such as easter or anniversaries) fall on weekends.