Casio 3145 Manual page 63

Barometric Pressure Graph
Barometric pressure indicates changes in the atmosphere. By monitoring
these changes you can predict the weather with reasonable accuracy.
This watch takes barometric pressure readings automatically every two hours
(at the top of each even-numbered hour), regardless of its current mode.
Measurement results are used to produce barometric pressure graph and
barometric pressure change indicator readings.
The barometric pressure graph shows the results of previous measurements
for up to 24 hours. The horizontal axis of the graph represents time, with each
dot standing for two hours. The rightmost dot represents the most recent
reading. The vertical axis of the graph represents barometric pressure, with
each dot standing for the relative difference between its reading and that of
the dots next to it. Each dot represents 1hPa.
The following shows how to interpret the data that appears on the barometric
pressure graph.
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