I'll start as I just posted this in another thread.
My personal record is -46C with the wind chill making it feel like -55C.
That would be about -67 Fahrenheit for you U.S folks.
We were ice fishing on Tobin Lake and had an old Trek 830 Antelope as our "ice bike".
And no, this wasn't a 40km ride. It was from our shack on the ice to the truck and back which was about 1km. But we did this many times during the day to get our food and "antifreeze" and to start and shut off the truck.
I was wearing my Canada Goose parka and pants with Sorel Glacier boots. And only those that have pedaled in Sorel's know how funny it looks!