The compass in Suunto Core automatically calibrates itself as you use it, but it may need to be calibrated manually in the following circumstances:
- The battery has been changed.
- The service menu has been accessed.
- The watch has been near a large amount of metal (e.g. in an airplane).
- The watch as been near a magnet or a strong electro-magnetic field.
- The compass has not been used for a long time.
To calibrate the compass, enter compass mode. While hold the watch level, and start slowly rotating it. 3-4 full rotations should normally be enough to calibrate the compass. If the watch has been near a magnet/magnetic field, you may need to rotate it a few more times. Keep rotating compass reading appears.
NOTE: The compass deactivates after 60 seconds. This is a power saving feature. Press the Start/Stop button to reactivate the compass.