I can't speak for northern Vermont, but FWIW, when I was up in the Nash Stream area during the weekend of June 7th- 8th, I found the bugs to be atrocious, just about the worst I've ever encountered. Flash forward to the 21st and 22nd, when I did Black Cap and East Huntington, and they seemed to have died off quite a bit, back to tolerable levels.
But, we'll still have mosquitoes for the rest of the summer.
i have not had a problem with bugs, probably because every time in hike in VT it seems to be heavy steady rain!!! when will this weather pattern end???