Last week people in my club were making comments about my wool jersey, full finger gloves and Lycra tights when it was 70 degrees and sunny. I knew it was going to drop into the mid to high 60s by the end of the ride, and as the sun got lower I'd be chilly. I was dressed perfectly. 
Perfect for me is 80-85. I'm not particular about the humidity - I'm not a huge fan of high humidity, but I don't mind it. One thing about high humidity is it really concentrates the flower aromas, and I just love that!
But no wind. I hate wind. For itself, and for the way it stirs up the pollen.
Speed comes from what you put behind you. - Judi Ketteler