reference source available.
For example, if you are standing at a trail head and know
the correct altitude, then the most accurate calibration will
be obtained by calibrating within ALTI mode (since it relies
on altitude as the reference). However, if you don’t know
your altitude, you can find out the current sea level pres-
sure (published online or in a newspaper) and calibrate the
sensor within BARO mode. For example, the U.S. weather
service publishes the sea-level pressure for all of its
stations at http://www.weather.gov
Temperature Accuracy
When worn on your wrist, the thermometer reading is
affected by body heat and may report a temperature
different from the actual air temperature by 10 degrees or
more. Long periods of exposure to direct sunlight may also
affect the accuracy. Try wearing the watch outside your
and then again whenever you experience significant
changes in altitude or temperature during your activity.
If you are not using the altimeter feature, then daily
calibration will maintain the accuracy of the barometer
and weather forecasting feature.
Whenever possible, the sensor should be calibrated soon
after you experience significant temperature changes.
Do I need to calibrate both the Barometer and the
Altimeter?
No. BARO mode calibrates the sensor based upon the sea
level air pressure, while ALTI allows you to calibrate the
sensor by telling the watch about your current altitude.
Calibration performed in either mode will calibrate the
sensor for all modes. For the best accuracy, we recom-
mend that you choose only one calibration method each
time you calibrate the sensor, based on the most accurate
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