Should a Dall’s sheep hunter above tree line in the Alaska Range worry about how altitude changes trajectory? No, because tree line here is generally at an altitude below 4,000 feet. Many of what appear to be towering peaks top out at less than 6,000 feet. I shot this ram at about 5,000 feet above sea level, making no compensation for altitude changes to trajectory.
Temperature also changes with altitude. In general, temperatures at higher altitudes are lower than at lower altitudes. On average it drops 3.5 degrees F. for every 1,000 feet you go up. Our 40-degree temp at 1,000 feet would fall to about 15.5 degrees at 8,000 feet. So while drag decreases because air is thinner near snowcapped mountain tops, colder air on snowcapped mountain tops increases air density, offsetting some of the altitude density effects. Temperature, then, works to ameliorate air density changes at altitude.
Whew! Who’d have imagined a little change in altitude could introduce such complexities? But how much difference will this make at 8,000 feet? Let’s build a trajectory table using the same load as above, but factor in the probable temperature difference at 8,000 feet.
8,000-Foot Trajectory at 15.5-Degrees
Source
How Altitude Changes Trajectory — Ron Spomer Outdoors is written by Ron Spomer for www.ronspomeroutdoors.com