As a local desert rat in Vegas that has been flying here for a few years I know from season to season where my needles will be. I use YS engines and every one of them will start out in the summer perfectly, once set I don't change the needles until our weather starts to drop from our 100 plus degrees. At about 60 degrees I have to open up the high end one click. At about 40 another click and by the time we get into the mid 20s I will have the engines about 4 clicks fatter. The difference doesn't seem to change on the low end so it is almost never touched. We are now in the 90s so I have been leaning them out again as needed. Your OS may react a bit different but it shouldn't be much.