I've done a lot of cold weather riding, down to 0F/-17F windchill, but I was prepared for it and dressed appropriately. I don't ride in the winter unless the forecast is clear. The worst is when bad weather comes in unexpectedly. A couple Septembers ago I was bike packing in Maine and a thunderstorm rolled in and dropped the temp into the 40's and I only had a light windbreaker. I was chilled to the bone and had to get on the road and find a motel that night to warm up.