Absolute pressure is the measured atmospheric pressure.

Absolute pressure is not corrected to sea-level conditions.

To compare pressure conditions from one location to another, meteorologists correct pressure to sea-level conditions (referred to as relative pressure, or pressure relative to sea-level).

Because the air pressure decreases as you rise in altitude, the sea-level corrected pressure (the pressure your location would be at if located at sea-level) is higher than your measured pressure if you live above sea-level and lower than your measured pressure if you live below sea-level.

The following is the absolute pressure lapse rate as a function of altitude for standard day conditions:

Relative pressure is the atmospheric pressure corrected to sea-level conditions.

To compare pressure conditions from one location to another, meteorologists correct the measured pressure (referred to as absolute pressure) to sea-level conditions. Because the air pressure decreases as you rise in altitude, the sea-level corrected pressure (the pressure your location would be at if located at sea-level) is higher than your measured pressure if you live above sea-level and lower than your measured pressure if you live below sea-level.

Relative pressure is larger than absolute pressure unless you live at or below sea-level.

You can check your local airport’s pressure here:

https://www.wunderground.com/

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