When we were planning for 2013, we used the 2012 calendar to make educated guesses when the parties would be held for the following year. I think the first party was on the 10th last year, the 11the year before that, and that would mean it's LIKELY to start on the 9th this year...and follow the same days of the week patterns of the previous years. Ultimately, the parties fell on the dates we predicted they would by using this method. Still, no guarantees they won't shake things up.