When promoting your self-published book, the social media tool Facebook ought to play an important role in the marketing strategy. Knowing when to post on Facebook, however, can maximize your efforts.

According to a number of studies, the best time to post is weekdays 1-4 p.m. Those hours result in higher click-throughs than posts made at other times.

That’s because more people are on Facebook during the afternoon while at work. Peak usage is Wednesdays at 3 p.m. Given that the primary users of Facebooks are working adults (not to mention how boring so many workplaces are), that shouldn’t be surprising.

Of course, these times are relative. If your business is national, you need to post over a longer spread of time than 1-4 p.m. in your time zone, or you’ll miss the peak times in other parts of the country. For example, if your business is based in Chicago (Central Time), you would aim messages for the East Coast (i.e. New York City, Boston, Washington DC) at noon to 3 p.m. Central Time and messages for the West Coast (i.e. Los Angeles, San Francisco, Seattle) at 3-6 p.m. Central Time.

Add a photo to increase readership of your posts. Photos result in 53% more likes and 104% more comments than a mere text post.

The absolute worst time to post is before 8 a.m., after 8 p.m., and on weekends. Though people are on Facebook during those times, the number of users drops considerably compared to the earlier mentioned peak hours.