Hmmm... I took a half a size down? I never size down?
Now that is odd! Just goes to show, everyone's feet are different! I have been sizing down to a 38 - sometimes even 37.5 - with most of the newer styles, but I could have easily fit a 38.5 comfortably in the Summerissima. I ordered a 38 which will work fine based on the pair I tried on at Barneys yesterday.