I was surprised when my most accurate PCP (my P35-22) shot a couple sub-190 30 yard challenge targets. I think the secret is the barrel was dirty but in my investigations I was also surprised to find the velocity was about 40 fps slower than in the summer. About 5% lower. I looked up the specific heat difference and from 85 F to freezing it was only about 1% lower. Some may be lubricant on the hammer thickening up but I also wonder if some is not the little bit of water in the compressed air. It's really dry here now and definitely not at all dry in the summer. I don't think I am at 100% relative humidity at 300 bar even in the summer. I see no evidence of condensation inside the air chamber of the gun. But it seems logical that there may still be a little more water in the compressed air in the summer. And less in the winter. Could the lower specific heat of the compressed air be a large part of the reason our airguns shoot slower in the winter?