If we look at the Seasonal Buying Patterns chart, we can see when all the closings over the past 3 years have occured.  The three months with the highest number of closings were January, May and October. 
Since this chart shows us the number of closings that occur in each month, we can also make some assumptions about when the properties are going into escrow and when it would be the best time to put your property on the market.  If we assume an average escrow takes 30 days to close (mostly 'all cash' purchases in Island Colony), then the best periods to sell, would be March/April followed by August/September and November/December.
Overall, I think the closings are pretty evenly distributed.  So there really is not a "bad" time to try and sell in the Island Colony, because even the slowest months have had 4 closings (ie. September).