The manual to a Sony camcorder I bought in the 90's gave a great solution to this:
If you are shooting in very cold temperatures, place your camera in an airtight plastic bag while you are still outside. After bringing it in to warmer temperatures, allow 30 minutes for the air inside the bag to acclimate to the new environment. As stated above, this super-easy precaution could save you money better spent on more gear!
It's usually not that cold where I live, but one winter when it was well below freezing I used this trick with a small clear garbage bag and it worked great.
