That seems backwards. If the day isn't switching over at midnight pacific, and follows east cost, it should actually flip over 3 hours earlier (midnight eastern time).
If it isn't tied to actual time, 3am makes as much sense as any other time, but the site does not appear to be in east coast time to me; it might be based on your own settings. I'm in central time zone right now, and all the times appear to be pacific to me.