I don't typically think of gray as a summery color. I tend to reserve it for clothes I wear in fall and winter. However, I recently bought a super-soft gray wrap dress and it feels so right, even now in the height of summer.
But then I noticed the gorgeous gray dresses in Donna Karan's spring 2010 ready-to-wear collection on style.com. So beautiful! There really is something to be said for the hue, no matter the time of year.
Photos from here.