The problem with that argument is you don't know what binder resin was used in your bike. It is not the carbon fiber that is affected by the cold, it is what holds it together. The ski argument is a little skewed also, since ski's are flexible, so obviously that is not the same carbon fiber bonding agent that is in your bike frame.

However, as someone already stated, if the cold that a bike could be subject to while riding outside in the US was enough to cause a failure then it probably would have already happened, a law suit filed, and a new version of the "dork disc" applied to all carbon framed bikes.

I don't worry about it, but then I don't ride carbon wheels either. Of all all the stressed carbon componets on a bike, the rims have to be the most stressed.