We often get questions about the "right" time to post.
In the past, the exact posting time for a Facebook post was fairly important. In recent years, though, Facebook has moved towards a non-chronological feed of posts.
As a result, the time a post is made no longer matters significantly - the post will be shown at different times to different users over a several day period.
In short: don't agonize too much over it. Posting regularly and authentically matters more than the exact times you pick for your posts.