I kept a ninja gaiden one in my garage all this winter and it survived like 15-20 degree weather possibly colder so yeah youd be fine but i wouldnt reccomend it, i finally moved my machine inside two weeks ago.
The only thing youd really have to worry about is it getting wet. Since most cabs are made of some sort of fiber board, they don't take to well to getting wet. I don't think you'll have to worry too much about it in your garage.
