They may run about a half size large but fit well and feel great.  The little ventilation idea with the holes above the sole works really well to keep your feet cool.  Not great if you are going to be walking through really deep puddles but no issue in just plain rain.  Pretty comfortable for those of us on our feet most of the day.  Too bad the dog liked them so well he ate one.  Now I have 1 and 1/2 pairs.