Depends on the hatch - generally not much of a problem in August especially if late July has been dry. BUT - there's always a chance for bugs. Bug spray and a headnet are all I've ever bothered with and I've only worn the head net once in more than 50 trips.
It is all based on locality. We've had buggy sites and bug free sites on the same trip on the same lake in August. They are on the decline for sure. You probably won't need the bug jackets. A permethrin product for clothing, a DEET based repellent for exposed skin, and head nets should suffice.
"Many men go fishing all of their lives without knowing it is not fish they are after" ~ Henry David Thoreau
While typically they wind down in August, I don't think mosquitoes look at the calender. If it is warm enough, and there is enough standing water,there will be mosquitoes. All it takes is some heavy rains. I've seen clouds of them in late August before.
Agree ankle biters will likely be around. Might be some deer flies hanging around too.
We always bring the bug gear. It's light and you wont regret it EVER EVER EVER EVER if you need it. It also doubles up as an extra pillow. We've needed ours. All I can say is....better safe than sorry.
+1 on Diva's comment. Bugs are still out and may not bother you. However they may bother your wife and kids so let them have them. You won't regret it.
The amount of satisfaction you get from life depends largely on your own ingenuity, self-sufficiency, and resourcefulness. People who wait around for life to supply their satisfaction usually find boredom instead.
The best way to ensure a mosquito attack is to NOT be prepared for one. Always have repellent, always. I pretty much always take a head net too, just because it so small. I seldom wear it. In August I wouldn't bother with a net for the hammock unless I was planning to sleep in it. Of course, if it keeps raining like it has been one might reconsider that.
Not as bad as other times of year. Mosquitos will be pretty bad on portages and at dusk, so be prepared (deet and nets). Day time at camp or on the lake shouldn't be bad (spray). But it's a good time of year to go. Flies may occasionally bother you and they are nasty. The only thing you can do is move far away from them (they follow) and wear thick clothing, which is no fun if it's warm. They got through my hiking socks last year, so I'm thinking of thicker socks. But in a 5 day trip, we only had 2 brief encounters. Some say paper dryer fabric softener works, or something. Find a camp site exposed to the wind and have a great time.