What does the altimeter reading A3016 represent?

The altimeter reading A3016 indicates that the altimeter setting is 30.16 inches of mercury (in Hg). In METAR reports, the altimeter is usually expressed in inches of mercury or in hectopascals (hPa), and the ‘A’ prefix before the number signifies that the reading is in inches of mercury. The number following the 'A' shows the pressure in this format.

When interpreting METAR data, it's important to understand how altimeter settings affect aircraft altitude readings during flight. The altimeter setting is crucial for pilots to maintain proper altitude. The standard sea-level pressure is widely recognized as 29.92 in Hg, so any readings above or below this number help indicate whether the local atmospheric pressure is high or low relative to that standard.

In this context, the other options correspond to different units of measurement or values. For instance, the readings in hPa do not apply here since the 'A' specifies the measurement is in inches of mercury, and therefore do not relate directly to A3016.