What days of the week are the slowest for your forum, when you have the least amount of activity? I think for this board it is Wednesdays... they really seem to be the days when the brakes are slammed in terms of activity.
I would say that friday, saturday, sunday and monday a little bit. With tuesdays, wednesdays and thursdays having the most traffic.
Saturdays most amateur umpires are out working games. I have not been to my board several times on Saturday.
During the summer, most forums are typically slow, with vacations and activities. Normally, things are slow on all of my forums on the weekends.
Weekends are usually the slowest, with activity dropping by as much as a third. It annoys more than just me : )
My board is mostly a ghost town on Mondays. Infact most of the week too. Weekends seem to bring life to the forum.