I dont have specific numbers or anything, but DeHavilland aircraft are famous for being able to handle extreme conditions. The most famous operator of DeHavilland aircraft is Greenland Air (DH7), which flies into Arctic temperatures on a daily basis during the winter. I dont think that the DH8 is as renowned for its cold weather handling as say, the DH7 was, but in Canada & Alaska DeHavilland aircraft often operated with perfect safety records. The DH aircraft air also specially designed to handle less than perfect runway conditions...another requisite for winter flying.
America's chickens are coming home to rooooost!