Frankly, it's been my experience that temperature sensitivity of powder has been much overblown lately.
Living in Upstate NY, I see temps in the single digits (even below zero F, occasionally) up to the 80's and 90's.
I would agree with Rapier that it's wise to develop loads at more moderate temperatures- who wants to work up loads in the cold, anyway?
Rocky, I am, shall we say, extremely sceptical of that temp/velocity change formula. My chronograph shows much less difference- and I have chronographed loads worked up in the summer at winter temps. I rarely see more than 100 fps variation, if that. And I pay no attention whatsoever to whether a powder is 'temperature sensitive'.
One man's opinion- your mileage may vary.
