ORIGINAL: NCIS
As for me, I'll stick to 55 and above. I lived in Houston Texas for about 20 years after moving down there from here and when I got home I just can't stand the cold anymore. My blood thinned out and it won't thicken back up.
Gibbs
Now there's the voice of experience.
Strangely I too established 55 degrees as my cut off point. Above that I fly, below that, only if it is warming up quickly.