What are the standard atmospheric conditions at sea level?

The standard atmospheric conditions at sea level are defined by a temperature of 15 degrees Celsius, a pressure of 29.92 inches of mercury (inHg), and a pressure of 1013.25 hectopascals (hPa). This set of values is established by international agreement and is used as a baseline for various calculations in meteorology and aviation.

The temperature of 15 degrees Celsius is significant because it reflects what is deemed a "standard" temperature at sea level, allowing pilots and meteorologists to make consistent and reliable measurements and comparisons. The pressure value of 29.92 inHg is traditionally used in aviation, and the metric equivalent of 1013.25 hPa is also important for those using metric measurements. Both pressure values indicate the same atmospheric weight and correlate with the physical state of the atmosphere under these standard conditions.

Utilizing these values allows for accurate calculations relative to altitude, performance metrics of aircraft, and other critical aviation parameters, thereby ensuring safety and efficiency in flight operations.