I don't know about the temperature sensitivity of 2015. It is a bench rest powder so it may not be designed to be used over a wide temp range. Call Western Powders (406) 232-0422 and they should be able to tell you.
Temperature varients will affect ballistics regardless of powder sensitivity though. Expect to gain about 1MOA of elevation (at sea level) for every 20deg rise in temp. This depends on other factors too, BC, MV, etc so there is no substitute for a trip to the range (oh darn, Honey, I have to go shooting again, LOL).