Module No. 5682
The watch takes altitude readings and displays results based on air pressure measurements taken by a built-in pressure sensor.
The altitude readings displayed by the watch are relative values that are calculated based on barometric pressure measured by the watch’s pressure sensor. This means that barometric pressure changes due to weather can cause altitude readings taken at the same location to be different. Also note that the value displayed by the watch may be different from the actual elevation and/or sea level elevation indicated for the area where you are located. When using the watch’s altimeter while mountain climbing, it is recommended that you regularly calibrate its readings in accordance with local altitude (elevation) indications.
Check the information at the link below to find out about how to minimize differences between readings produced by the watch, and values provided by local altitude (elevation) indications.