Storing bicycle in a shed for the winter
http://velonews.competitor.com/2010/04/bikes-and-tech/technical-faq/technical-faq-carbon-in-cold-conditions_111530 summarises to "No problems"


  CF (carbon fibre) components are used extensively in launch/reentry
  vehicles and satellites where the temperatures range from superheated
  to near absolute zero. The ultra low CTE (Coefficient of Thermal
  Expansion) of carbon fibre make it ideal for these temperature
  extremes. I find it very hard to believe that a bicycle sustained
  damage during winter storage in a cold garage – regardless of the
  earthly location. I have seen “green” (not fully cured) paints and top
  coats crack in extreme temperature conditions but never a CF composite
  structure.


Although if your bike had water in it and that froze, you would have a different problem.   To deal with this, dry your bike, and hang your bike so it drains - often there are two breather/drainholes at the aft end of the chainstays... but do eyeball them first.