N/A TalonP VS. Temp

hello fine air gunners. got a question for you guys, this has been posted before but the results were less than ideal so here it goes again. I just roughly set up my Airforce TalonP to shoot the 26.54 hades at about 850-880 fps. it is currently 21 degrees F, I am wondering how temperature will affect my velocity. I am fully expecting the velocity to go up as the temp goes up, but by how much? im seeing some people reporting almost 50fps, and others saying as little as 10 fps. what you guys think? of course ill update this post or make a new one in the summer and compare numbers with higher temps.