I don't know whether higher nitro could be considered a requirement for cold weather flying? I don't think it should matter. I flew mine a few weeks ago when it was about 45F and last week at about 65F, ran fine both days (I don't remember having to make any adjustments either).

I've also ran Coolpower 15% with no problems. Heli still flies great, not that I do anything too exiting with it.

Ben