The thing is not how cold the winter is but how long it lasts.
Halifax has almost no spring, short summer, beautiful fall and half year winter.
When people in other part of the north america are enjoying the beauty of spring, we are still in winter, it's so so long and so depressing.
That's why people treasure every moment of summer.
People stay indoor most of the winter, so that -20C is not a big deal. But still you long for the warmth from sun shine, longer season for your flowers and all kinds of outdoor activities
But don't be intimidated... be prepared.