This is off the cuff and a suggestion. A lot of members attending this convention were from the Northeast. This may reflect UAMCC membership in general, but I am not sure.
I'm not too sure about true pressure washers, but wood companies are typically still working in October, and often into November. Due to mild, dry weather forecast for the next 6 days, we are working.
From a selfish standpoint, the 2nd or 3rd week in Nov. would be ideal. One other thing to consider.
Many companies are seasonal, depending on geographic location. By late fall, we're flush with cash in the bank. By early spring, some of us smaller contractors are a bit thin in the cash department. This may be a detriment to attendance due to seasonal cash flow.