What unit is pressure change reported in within a METAR?

In a METAR report, pressure changes are typically reported in tenths of millibars. This is a standard practice in aviation meteorology, where atmospheric pressure is an essential element for aviation safety and flight operations.

Millibars are a common unit for measuring atmospheric pressure, and the use of tenths of millibars allows for more precise reporting, which is important for pilots and air traffic controllers. By expressing pressure in this way, it is easier to notice small variations in pressure that can affect weather patterns and aircraft performance.

While other units like inches of mercury or pascals may be used in different contexts, they are not standard for pressure changes in METARs. The focus on tenths of millibars provides clarity and consistency in the data presented to aviation professionals.