What is the standard atmospheric pressure on a "standard day"?

The standard atmospheric pressure on a "standard day" is defined as 29.92 inches of mercury (inHg) at sea level and at a temperature of 15 degrees Celsius (59 degrees Fahrenheit). This value is crucial for pilots and meteorologists as it establishes a baseline for calculating altitude and aircraft performance.

This standardization is part of the International Standard Atmosphere (ISA), which provides a model for various atmospheric conditions. The significance of using 29.92 inHg lies in its role in calibrating altimeters, ensuring uniformity in altitude readings regardless of local weather conditions. Pilots rely on this standardized pressure setting to maintain accurate altitude and make informed decisions during flight planning and operations.

The other values presented do not represent the standard pressure. For instance, 29.2 inHg, 29.7 inHg, and 30.0 inHg may be relevant under specific conditions or locations but are not universally recognized as the nominal atmospheric pressure on a standard day.