I wear an undershirt (Indian variation of a wifebeater), a t-shirt and a full sleeve shirt in Michigan summer. The layering is for comfort and I got into the habit of a full sleeve shirt a couple of years ago when I had psoriasis (sp?) outbreak and I was really embarrased of the skin marks. I never outgrew the habit of wearing a full sleeve shirt. I also wear them in dark colors (my taste in clothes).
People look at me funny, some friends and family members crack jokes but I don't care. I don't sweat much, I can handle the heat and I don't need an A/C to survive the summer (I set the house A/C at 85F (+) when I am home alone.