Everything that's not impossible is inevitable. People really need to keep that in mind. Way down south is doesn't do this often but as seen this week, it happens occasionally. There's no reason not to have some preparations for this even if it's just a couple of sleeping bags, a down comforter or extra blankets. In Bozeman we're usually under 80 in the summer and it doesn't get below zero all that often in the winter, or at least now for long periods. But we had triple digits last summer and it occasionally gets down to -35 F in the winter, so it's good to be prepared for both.