PO box access open when the post office is closed?

It's a little late for your answer, but I just googled it, because I also needed to know about P.O.Box accessibility. As of Sunday, June 19, 2019, P. O. Box accessibility is from 4:30 am until 6:30 pm. Hope that helps. Helped me from making the drive today, from Mo Val, lol.

I believe it's 6:00 a.m. till 6:00 p.m. for PO box access.