I'm not of the opinion that lots of hydration in cold temperatures will mitigate cramps. Cramping reasons can be a bit complex - its not always hydration. Being active gets the kidneys going. Maybe warm up on the trainer at home about 15 minutes before going out to ride. And as Carbonfiberboy said, you only need shorts and tights (no bibs). I also concur that a blood test is in order just to be sure there is no underlying issue.