The specific day a few of the more recent NASA astronaut classes were announced (Mostly near start of month)

[Christopher Lusardi]

NASA Astronaut group announcement dates:

23: 12/6/2021 https://en.wikipedia.org/wiki/NASA_Astronaut_Group_23

22: 6/7/2017 https://en.wikipedia.org/wiki/NASA_Astronaut_Group_22

21: 6/4/2013  https://www.nasa.gov/history/25-years-ago-nasa-selects-25-new-astronauts-for-the-class-of-1998/

20: 6/29/2009 https://www.americaspace.com/2019/06/30/a-decade-of-chumps-nasas-2009-astronaut-class-chalks-up-ten-years-of-space-experience/#:~:text=The%20selection%20process%20had%20begun,after%20the%20legendary%20Mercury%20Seven

19: 4/6/2004 https://www.nasa.gov/history/20-years-ago-nasa-selects-its-19th-group-of-astronauts/