Anyone Riding in Sub-Zero Fahrenheit?
Yes ... often.
When I lived in Winnipeg, I commuted by bicycle year round ... in temps as low as -40C/F. I preferred that to scraping ice off car windows, and then sitting inside the freezing car on rock solid seats waiting for some teensy bit of heat to emerge from the vents.
And ... a little story for your reading enjoyment about a century I did late in February in 2003 in Winnipeg ...
http://www.machka.net/brevet/Coldest_Century.htm
I've done several more centuries (and somewhat shorter rides) in slightly warmer temps than that ... like -18C, -20C, -22C ...