I am often asked by clients the best time to post on their Facebook business page. It is different for every client, product and service.
Login to your Facebook page – go to Insights/Posts and it will show you the days of the week. Hover over the day with the highest number, and time at the highest peak.
This clients best time to post (based on previous posts) is Saturday at 9pm.
Use this to schedule future posts for highest reach.