I remember a winter in Sault Ste. Siberia, MI, that the temperature was 32 degrees below zero. My car refused to start and I called a tow truck to give me a jump. They came to my house and tried to jump the car, but nothing happened. They told me that I would just have to wait until it thawed out.
I couldn't figure out why it couldn't be jumped so I looked it up. This is what I found:
The problem usually has nothing to do with the battery, but with the oil. Freezing temperatures tend to turn you oil into a thick syrup making your battery work harder to turn the engine over. Manufacturers make higher amp batteries that may help alleviate this problem or you may want to consider a heated blanket to keep the moto oil from becoming a semi-solid.
I think the bigger problem is that my car had an aluminum block and nothing was going to make that car run in those temps. I went out and bought the heated blanket, plugged the car in and waited. Voila, it started!