[Piotrsko]

There's density altitude app computers for your phone, but they require an accurate base altitude. High air temperature tends to make the air less dense which is a minor drag improvement but can also make stuff draggy as boundary layer can go non laminar.

Heaters in Huntsville? Until it gets to below 40f and I had to take the F250, I wore a coat. Didn't have the heat efficient so window defrost was the issue.