It depends on the breeder. Some are more equipped to ship in cold weather than others. No breeder in their right of mind will send a crestie if they are not positive it will make the trip.

Have you considered Twin Cities Reptiles (on University Ave. in St. Paul)? I don't recall seeing any cresties there on my last visit but the place is enormous, so I probably overlooked them. They take very good care of their animals and have a very wide variety.