Hickory and boo have a reputation for taking up water quickly, and losing strenght and resilence as a result. There are two schools of thought, at least, as David said. One is to build the bow in the ambient conditions so it doesn't change if you don't or can't artificially dry it. Other is to minimize moisture content during contruction and use, to get the most out of the material. I would fall in the middle. You will probably enjoy 15% to 20% lower average Rh during the winter hunting season in your area. So I'd try to build it at around 40% Rh so when winter rolls around it won't be the 5# or more heavier in that environment than when you build it. Also will help keep set to a minimum, which will rob performance for the life of the bow. Downside is if you use it much in the summer, you'll want to try to keep the moisture content ireasonably low, inside of 50% anyway.