I don’t doubt Steve’s physical and psychological ability to cope with cold temperatures, but cold temperatures unavoidably slow you down.
If you change the air temperature on
Bike Calculator from the default to −10°C while leaving alone all the other defaults, the speed drops over 1 km/h just from the increased density of cold air. In reality, speed drops more because bulky clothing is needed that compounds the increase in drag, tyres have higher rolling resistance at lower temperatures, and the body has more difficulty producing power in those temperatures while surviving.
Go Steve! I have followed these years in awe.