The cold can really take a toll on the batteries more than anything. Hopefully someone can come up with the 'chart' that shows how the available voltage decreases when the temp takes a nose dive.
Many cars/trucks can be purchased new with a factory option engine heater that also includes a battery blanket (kinda like an nitty bitty heating pad).
Around here many, if not most folks do have a garage. When I lived in Alaska, I'd venture to say 90% of vehicles I saw had the plug-in for engine heaters whether or not they had a garage (the cold up there was looong termed vice what we have in the lower 48). Many 'work places' had available 120V outlets for just that purpose.
Bill
