Black flies are only in may, followed by mosquitoes just after. July, in the woods, Deer Flies can be bad. On the water no flies will bother you either month. August has cooler nights but still comfortable. Unless you are going for a nature hike in the woods during the day, either month is good. Personally, August is my favorite for camping. June will have mosquitoes mainly when the sun goes down or up, August won't.