One of the few perks of living in Utah is that we dont get the extreme weather swings. It gets cold in the winter and hot in the summer, but not like in other places. I do my load development in the summer to ensure saftey and then double check them in the winter. I use w-760 for some of my best loads and I have found that the most velocity I have lost was less than 50 fs and poi variation was a total non factor. I dont even worry about it anymore.