Dave, I think it depends where you live in the US. Seems like it's too muggy in the south to drive Cobras in the summer. You probably don't drive on hot, muggy days or when it's raining (most of July?) there, so your driving season may not involve most of the summer. I hear that region is the rainiest in the eastern US. We, on the other hand have relatively low humidity air, and for the most part, dry sunny days.
Although Mike lives up in the mountains, he should get close to 6 months of clear roads on an average year. I live south of Denver so I can drive almost year round, if I'm willing to put up with a little sand on the road during mid-Nov to about March-April. The snow storms here are short and snow can melt within hours or a day since it's usually sunny. Motorcycles are everywhere as soon as the roads are clear. I can head out the back roads where there is little traffic to follow that can blast my car with sand/gravel.
I'm just a few miles away from hitting 5200 in 14 months of driving my GT. How many miles were you able to drive the past 12 months?