this happens with any camera -- my olympus XA froze up on a bike ride a bit ago, I've seen Nikon Fs freeze up -- 27 is pretty cold -- keep the camera inside your jacket until you shoot so it stays warm enough. -- you don't want it so cold that it gets misty from precipitation when you take it back in the house either.
if your camera does freeze up DO NOT FORCE IT. Just put it inside ur coat and let it warm up.
If you are going to use it in the freezing cold a lot, like that upcoming treck to the South Pole by ski pulling sledges (take lots of vitamin C!!!) you an have it weatherized with thinner lubes.
Another thing to watch out for -- frozen film can break, and generate static electricity that leaves lovely flashes on your film, so wind slowly in the cold.