There is a another good reason for going to 700c if you ride in the wet. More fender clearance; hence allowing bigger tires and more tread choices. (I try to buy 27" wheeled bikes as winter/city/rain bikes and set them up with 700c wheels. Now that gravel and other trends have happened, modern bikes with tons of clearance are available but for a long stretch, needing that clearance limited your options so I kept buying early '80s Japanese bikes and the like.)