Under what conditions is density altitude equal to field elevation?

Density altitude is a measure that reflects how the altitude of a location changes in response to variations in air density. Under standard atmospheric conditions, which are defined as a temperature of 15 degrees Celsius (59 degrees Fahrenheit) at sea level and a standard atmospheric pressure of 29.92 inches of mercury, the density altitude and field elevation are the same.

When atmospheric conditions are standard, the altimeter settings and temperature correspond directly to the elevations provided on aeronautical charts. Therefore, density altitude equal to field elevation occurs because the factors affecting air density—such as temperature, pressure, and humidity—are balanced in a way that mirrors those standard atmospheric conditions.

In scenarios where atmospheric conditions deviate from these standards, such as being extremely humid or at different temperatures, the density altitude will not equal the field elevation because those conditions impact air density. Similarly, at sea level or on humid days, the air temperature and pressure may vary enough that density altitude would differ from field elevation.