I run 23c's all year round in Chicago, you just gotta be careful when you lean turn in to corner and you learn what kind of crap your tire can cut through while cornering vs straight line riding. Where I live there are always tire tracks to follow, so its mostly mushy melting slush and snow at the worst, hardly any hard pack or undodge-able ice chunks. I'd say if your city is decent at plowing and uses ice melter you could maybe get away with it. If you city uses sand its best to find an alternative to skinny tires.