It sounds to me like you have two things happening, a weak recoil spring, and freezing temperatures increasing the viscosity of the lubricant. I would fix the spring first, and that might take care of it. But if you have to have a gun operate at extremely low temperatures, try a dry lubricant like Remington RemDriLube. It's an aerosol that sprays on. The solvent quickly evaporates and leaves a dry film of teflon on the moving parts, which works extremely well as a super cold weather lubricant. It also doesn't trap burnt powder and other foreign matter like oils do.
I have been using this for my semi-auto shotgun for years. As a duck hunter, you see a lot of extreme weather conditions, and this stuff just plain works for 100% reliability. Nothing in the form of oils will work as reliably, especially in the cold extremes. It also works great for semi-auto .22's in freezing cold weather, where the low recoil energy is too easily impeded by thickening oils at sub-zero temperatures.
I wouldn't recommend using this stuff all the time in moderate temperatures. I don't think it has the protective properties that oils and grease do, especially for extended (>100rds) shooting sessions. But if you have to have a cold weather gun with 100% reliability, this stuff is great.
I think someone also makes a similar product except the dry lubricant is graphite. Same concept. This stuff is also awesome for spraying into sticky locks, since the solvent cleans out the gunk and the dry teflon residue left behind doesn't attract or retain other foreign matter, so it won't gunk up again.
Since I carry my G20 IWB, it never gets cold enough that I have to worry about the cold thickening oil.