I’ve seen a few rods break in the cold (15-25F) but don’t know which ones are in the most danger. 

 

would higher ton carbon be less or more likely to fracture in extreme cold? Glass better? What about graphene/g-rods?

I’ve never broken a rod and I’ve fished in temps down into the teens

I've broken several rods but it was stupidity not temps that broke them.

Use the same rods you use in summer. Temp has nothing to do with it. Being careful does.

Whatever anecdotal evidence you may have witnessed or heard , cold has no affect on rods. 

I fish all winter long in our extreme cold temps and even with the moisture from the steam coming off the heated water freezing to my rods I don't break rods. 

??