I lived in Mass for a few years and I used a simple 'battery Buddy' and it worked real well. If a batt is low and freezes it can (and most likely will) warp the plates inside causing them to contact each other thus shorting out some of the cells. This will cause the battery to fail in keeping a charge. I saw in the Want AD magazine a 1996 500SL that had 10K miles for sale because it was stored for many years and someone tried to jump start it causing significant damage to the electrical system, including the electric speedometer. Therefore when it was sold the reg had to suggest "milage unknown" This car had the original tires and the wind screen still had the plastic wrap on it in the trunk..... LIKE NEW CAR $15K... Salvage title!!!
In short, Don't jump start the car!! $100 dollars for a good batt... Thousands for a jump start.