I had my roof down yesterday for about 70 miles. Temp was mid 70's and I was on the freeway most of those miles at 65 - 70 MPH. I found that having the drivers window up kept wind buffeting to a minimum and the temp was just right. It was a great day to be riding in a convertible.
Doesn't anyone drive with their top down ? I've probably put 3 or 4,000 miles on with the top down this summer. Usually these are drives in the early morning or late afternoon/evening. My wife and I love riding up in the mountains with the top down, it's almost as good as being on my motorcycle, and much more comfortable.