I have found that the best time to post is when you get the urge, we are an International community of people who are every now and again, so based on that, whatever you post will get seen by some at some point of time.
I have spent a bit of time analyzing Appics and have actually found a pattern, however that pattern is determined on what you post, so really there is no pattern
What people will read and what they like is always subjective and you may find a subject matter that gets initial attention but most people are not consistent in viewing, .
So the Best time is Now, Now, Now and even Now