Air density is what effects the trajectory. As a general rule, the higher the elevation, the lower the air density. However, weather patterns change air pressure and thus air density, as does temperature. Buy a Kestrel weather instrument. It will provide "density altitude" and/or a true atmospheric pressure, which is the key to evaluating the real effect on the trajectory, and plug that into ballistic software. There are several which can be downloaded on a phone for $10 - $15.
Also, take a chronograph with you if you can. Velocity will change with the temperatures, the question is how much. Even the Hodgdon Extreme powders change somewhat with temperatures, just less than others.
Another factor to consider, shooting at angles, up or down, decrease the horizontal distance to the target, and thus, decrease the elevation correction required.
For long range shooting, all factors matter.
