This is not true, Air pressure and Temperature you need to care about. Air density affects accuracy. Standard air temperature is 59 degrees Fahrenheit and barometric pressure is 29.92 inches of mercury. As air pressure increases, air density generally increases. This slows rounds, which may cause them to strike low on the target. Firing when air density is less than average has the opposite effect. The tank’s computer compensates for this effect, using values input into the system. Recommended standard inputs for major geographical areas, by seasons, should be used whenever current information is not available. Always use the current, local barometric pressure and temperature, if it is available. Temperature should be updated whenever it deviates more than 10 degrees Fahrenheit from the indexed value; barometric pressure should be updated whenever it deviates more than one inch of mercury from the indexed value.