I'm no expert either but it's my understanding if you zero any rifle when its 80 and dry . Then go shoot it when it 30 and humid the gun will not shoot the same . that has to do with many factors . When the ammo/powder is hot/warm it will burn better/faster and create more pressure and you will shoot a little high and the opposite if zeroed when hot and then shooting in the cold you will most likely shoot low . I would also think if your barrel is very cold your POI will change quite a bit as it heats up from shooting . Now that's my understanding ( I am talking about the lighter sporter contour barrels ). If I'm wrong please refer to my first 3 words in this post .
Never experienced this with any of my rifles. All still shoot to zero.