Hello,
From a developers perspective... Right around 4am - 6am Eastern Time, I notice that my bots often drop usage by half. This means that there are less broadcaster's online, and probably less users. I see the greatest peak after 11am ET. This trend continues into the late evening. My bots often show the most users around 7pm - 2am ET.
These stats were gathered after watching my bot's perform for the last 2 years.
Cheers,
Cexmental