How much will the temperature (right now it is 25deg. in the summer it would be 75deg) affect the pressures that I get with a given load? something SAFE in the winter will the pressures go up with the temps?

Because it is double base, there will be a measurable decrease in velocity as temperatures drop and measurable pressure rises as temperature increases. Since I seldom develop full max loads in my cartridges, this has not been an issue. work the load up for safety during warmer months. I do have some cold weather load that are hotter and only use them during the colder months.
Dave

I haven't really found it more sensitive than normal.

I would not take RL22 or most powders and work up a MAX load at 25deg and then assume it would be safe at 75 or 100.

In my younger days I had a couple rifles with 2 loads one for cold one for hot. Now days I stop far enough back from the max that temperature isn't an issue.

I have used RL-22 in Africa at 95 degrees with a .358 STA on plainsgame, and in Colorado at -22 with the same rifle and load on Elk, with no percievable difference in performance. As for my use I have never experienced any problems with RL-22 being temperature sensitive after many years of extensive use. Good shooting.

I have chronographed RL-22 with a .300 Win. mag., 180 gr. bullets. The load was developed at 85 degrees ( shot over an Oheler 35 ) and then retested at 23 degrees ( Oheler 35 ) and the load lost two feet per second per degree of temperature decrease. I kept the rifle and ammo at ambient temperature. I have found that the Hodgdon Extreme powders don't give the fastest velocity at max load, but don't lose as much velocity in cold temperatures as a double base powder like RL-22. So, it is a wash. What ever shoots the most accurately would be my choice. Don't know what other combinations of caliber, bullet, or colder temperatures will result in, doesn't get much colder around here.
FWIW, just my experience.
Jim