It's interesting that no one has mentioned Density Altitude, it seems like it could be handy for aerodynamics. I come from a long range precision rifle background, it's used extensively in ballistics. I believe it's used in aviation too.

Essentially, it's a way for you to use the pressure, temperature and humidity to come up with an air density value. This would allow you to easily compare the density values from ride to ride.

https://www.youtube.com/watch?v=cXzbrGXI5Dw