Cold weather golf

Have there been any tests to show if shafts or balls respond differently to playing in temperatures less than 40 degrees? I use AP1 regular graphite irons and it seems I have less dispersion in my iron shots in colder playing conditions. I'm curious if the shafts play stiffer when cold (they feel stiffer), or is the ball spinning less?

Probably  little of both. I would recommend going to see a Titleist fitter and see if you should be playing a steel shaft.