Answer by Christian Verdú:
I agree with.
This being said, if you want to run your own experiments, you can find out about your blog´s audience implementing Google Analytics (http://www.google.com/analytics/). GoSquared (http://www.gosquared.com/) and GetClicky (http://getclicky.com/), if you´d rather go for real-time analytics, both offer a free plan. That is, if you´re blog is self-hosted or your hosting provider allows for insertion of a tracking code. This should give you an idea of when it´s best to publish.
As for communicationg about your post in social media, Hootsuite (http://www.hootsuite.com), for instance, will allow you track clicks and retweets for your tweets and find out what time works best. I recommend you schedule tweets at different hours (Hootsuite allows scheduling as well) and see which works best.