Hebrew in the Streets

Because it's actually fairly warm out, I decided to take a walk at lunch. I was walking down the street, when all of a sudden, I hear "Ma Nish Ma?" (Hebrew for "How are you?" I turned around and saw a guy looking at me, smiling. I smiled back and kind of waved, then hurried off before he could try to engage me in a conversation in Hebrew (since he would quickly discover just how poor my Hebrew is). For a minute, I couldn't figure out how the guy knew I was Jewish, since I don't look particularly Semitic, but I think it was my skirt that tipped him off.