First think about what kind of audience you will be targeting. Will they be global or pertain to a geographic location. Hubpages is read all over the world. Some read it throughout the day and othesr have either a morning routine or end of day. If you are writing on issues that effect say the east coast, then publish early in the morning! If it is the west coast...then later in the day. But really, it is all a gamble, just focus on writing a good quality article, with key phrases in both the title and body of article as well as your short summery so the search engines will pick them up.