Viewing Pressure History; Relative Pressure Calibration Discussion; Rain Display; Rain Increments Of Measure - Ambient Weather WH2902 User Manual

6.4.3 Viewing Pressure History

Press the [PRESSURE -] button to view the 12 hour, 24 hour, 48 hour and 72 hour pressure average.

6.4.4 Relative Pressure Calibration Discussion

To compare pressure conditions from one location to another, meteorologists correct 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 generally higher than your
measured pressure.
Thus, your absolute pressure may read 28.62 inHg (969 mb) at an altitude of 1000 feet (305 m), but
the relative pressure is 30.00 inHg (1016 mb).
The standard sea-level pressure is 29.92 in Hg (1013 mb). This is the average sea-level pressure
around the world. Relative pressure measurements greater than 29.92 inHg (1013 mb) are
considered high pressure and relative pressure measurements less than 29.92 inHg are considered low
pressure.
To determine the relative pressure for your location, locate an official reporting station near you (the
internet is the best source for real time barometer conditions, such as Weather.com or
Wunderground.com), and set your weather station to match the official reporting station.

6.5 Rain Display

6.5.1 Rain Increments of Measure

Press the RAIN button to switch between Rain Rate (in/hr), Rain Event, Rain Day, Rain Week, Rain
Month, and Rain Total.

6.5.2 Resetting Rain

To reset the rain totals, press and hold the RAIN button for two seconds.
 Resetting the weekly rain also resets the daily rain.
 Resetting the monthly rain also resets the daily and weekly rain.
Version 1.0
Figure 15
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