Suunto 9 Peak Pro constantly measures absolute air pressure using the built-in pressure sensor. Based on this measurement and your altitude reference value, it calculates altitude or air pressure.
Keep the area around the two air pressure sensor holes located at six o'clock on the side of your watch free of dirt and sand. Never insert any objects into the holes as this may damage the sensor.
From watch face, swipe left or press the middle button to scroll to the outdoor widget. The outdoor widget has three views that can be accessed by swiping up and down. The first view displays the current temperature, altitude and the barometric pressure.
Swipe up to see the barometer trend graph.
Swipe up again to see sun and moon data. You can see the time when the sun rises and sets, and also the current moon phase.
Swipe down or press and hold the middle button to go back.
Be sure to have your altitude reference value set correctly (see Altimeter). The altitude of your current location can be found from most topographic maps or major on-line map services such as Google Maps.
Changes in local weather conditions affect altitude readings. If local weather changes often, you should reset the altitude reference value regularly, preferably before starting your next journey.
Weather and altitude changes both cause a change in air pressure. To handle this, Suunto 9 Peak Pro automatically switches between interpreting changes in air pressure as altitude or weather changes based on your movement.
If your watch senses vertical movement, it switches to measuring altitude. When you are viewing the altitude graph, it is updated with a maximum delay of 10 seconds.
If you are at a constant altitude (less than 5 meters of vertical movement within 12 minutes), your watch interprets air pressure changes as weather changes and adjusts the barometer graph accordingly.