Living in Canada, "year round" riding is not an option for me. Having 5 foot high snowbanks from December until March make this impossible (again... for me!). However, in early spring or late fall, one of my biggest concerns when riding around the freezing temperature mark... manhole covers are something to keep an eye out for. Riding over one of those things can be going from "okay grip" to "NO grip" in a split second. Also, shaded areas, when riding downtown, are something to take notice of as well. Some mornings or evenings, where the sun feels like it has strength, can be very deceiving once you get to shaded areas. In the spots where you have sun, the pavement can be dry and still provide a reasonable amount of grip but, in shaded areas, you could still have that ever so slight difference of a couple of degrees where a thin sheet of ice still resides or is forming.