In case of rain, walking and strolling around isn't easy, or better say, you have to watch your steps. The fact is, pavements and staircases in whole the town are made out of stone which, during the centuries, became smooth and slippery. I felt down, pretty hard, steping down the stairs when entering into the cafe-bar on Pile. After it happened the locals explained me the right way; when raining one should stand down on the stair with entie sole, not with fingers like I did!
It's only a small danger, but I was surprised that I have not read any tips about the streets in Dubrovnik Old Town, which can be very slippy. I don't know how those women do it in their stilettos, I was struggling in my sensible sandals!