See also my personal HN analyses, although they are atleast a year old but the overall trends are still unchanged.
Analyzing submissions: http://minimaxir.com/2014/02/hacking-hacker-news/
Analyzing comments: http://minimaxir.com/2014/10/hn-comments-about-comments/
More recently I made a few charts about upvote probability by time slot: https://news.ycombinator.com/item?id=9864254