Cold weather = bad gas mileage?

[Kevin 1G Drummer]

My car doesn't take any longer to get to operating temperature when it's 7 degrees then it does when it's 70. Like Swanny said, rich mixtures burn cooler than lean mixes, so what Jet said, doesn't really make sense to me. The only reason I can see for an engine running a bit rich is because of the density of the air. I also don't totally buy the wheel bearing thing. I've worked on cars that had been sitting outside in the cold for days, and I haven't expierenced one that was a huge difference in resistance from one that was warm.