Personally, Mark I've always thought it was best when it wasn't raining or snowing.

I never really did care about the temp or the humidity...except as far as it affects my comfort between races. I know it affects your times and all but it affects everyone elses too. So on any given day, it should cancel out. Having a blower car, it supposedly has a worse effect on me than turboed or n/a cars but I try not to let that bother me. The "BEST TIME" thing is really overrated. What is important is how quick your car is overall in all conditions and just like you drive it on the street. It really puts a damper on things when a car with a slower "best" time at the track kicks the crap out of you everytime on the street.

Other than that...what they said up there.