So I'm a brand new student to flying. Yesterday I entered into discussion with my instructor about pressure systems and how they affect altimeter settings. My main area of confusion is how temperature plays in the equation. It is my understanding that as temperature rises air molecules spread apart resulting in less density. Less air density equals less pressure resulting in a higher altimeter reading. With that said, if you are flying from an area of low temp into an area of high temp, your altimeter would be reading warmer (less dense) air placing your altimeter at a higher than accurate altitude. This goes against the "low to high clear the sky". If the altimeter were left uncorrected, you would actually be flying lower to maintain altitude per your altimeter. Can anyone help identify where I am going wrong?