We have pretty normal autumn weather in Chicago right now, in that it's gray and cold with temperatures about 3°C below normal. Friday morning, when I fly out, temperatures will fall to 10°C below normal and then 13°C below normal when I get back Tuesday.
We have this ridiculous late-autumn chill because of climate change. Warm air over Greenland and the Grand Banks has distorted the circumpolar jet stream into an omega shape, bringing the Arctic to Canada and the central US and bringing California to Alaska. Check out the map.
I'll just have to drive to O'Hare and leave a winter coat in my car, I suppose.