Originally Posted by
Dreww10
I think most cyclists are aware of how the air density in cold temperatures effects aerodynamics and in turn their speed for a given effort, but what I haven't seen is discussion of whether this causes the wind to have a multiplied effect on a rider. I've often felt that below 60 degrees F or thereabouts, a given wind speed becomes noticeably more difficult to ride into, independent of the diminished speed already caused by the increased air density. For example, when it's in the 30's, an 8-10 mph headwind seems to have the slowing effect of a 20 mph wind in the summer, but still has the normal effect of a 10 mph wind when at your back and your side.
While aerodynamics plays a bit of a role in the speed reduction, I would say that is its minor compared to other factors listed in the VeloNews article above. Above about 60°C, we tend to wear less clothing and have fewer restrictions. Our heart doesn't have to work against the cooling of the skin...if anything the heart works more efficiently at higher temperatures because the skin is shedding heat as rapidly as possible so the capillaries are wide open.
When it is warmer, we are using more energy to power the vehicle than to simply keep the engine warm (so to speak). Simply taking in air requires a significant amount of energy to warm it.
There is also a psychological component to riding in the cold. Frankly we are little monkeys from a very warm part of the world. We don't
really like cold all that much and would rather be somewhere warm.
But we are also stubborn...and not a little dumb
... so we just keep pushing through the cold when all the smart animals are sleeping the winter away. Way back in the back of your head there is a voice that is saying "The bears have it right. What the hell am I doing out here?" But we just keep suffering. That's not usually good for performance.