I don't think a title like that needs much explanation. At this moment Weatherbug.com says its fourteen degrees with a wind chill of two degrees. If I was foolish enough to venture forth on two wheels today I would be facing wind chills hovering around minus twenty degrees. That is too cold for me these days.
Back in 1982 I made a fateful decision that exposed me to riding in this kind of weather and I paid the price. I had decided rather than fix a car I would ride my fairly new Kawasaki year round. It sounded like a good idea when I said it but I learned the folly  of my decision fairly quickly. Riding year round means traveling in the rain, wind, cold and scorching heat. Even dressed effectively couldn't overcome the chill of twelve degree temperatures coupled with a half hour ride at highway speeds. You would be amazed how much your hands can hurt when thawing out from forty degree below zero wind chills.
The other downside was that motorcycles aren't really built to withstand foul weather. The poor creature suffered extreme wear on components that usually last a lifetime of normal use. Bearings failed, sealing devices hardened and leaked and constant exposure to the sun faded the paint and caused the seat material to dry and crack. That the motorcycle made it to 100,000 miles was a testament to it's designers but it would have been in much better shape had it not been weathered upon during its early life.
When I finally had enough money set aside to purchase another car I did so with great enthusiasm. The motorcycle spent most of the next six months idle as I could hardly look at it without recalling the pain. Ultimately it was put back into use but I would never purposely set out in bad weather with it again. That painful lesson has saved my present fleet from the abuse of being used badly and they will live a good, long time as a result. Not to mention saving me from hours of discomfort.