Actually, Mike, the top vent is cracked open - in my case, it's about 1/8-inch - to act as an exhaust. I use my WSM w/DigiQ DX on an attached, screened-in back porch, and am surrounded by a privacy fence and houses on all sides; consequently, I don't know if that qualifies as being subject to wind speeds and gusts, but in any event, I've not experienced any significant differences in cooks conducted in windy vs still conditions. Hope that helps.
Regards,
Rooster