- Rapid changes in weather
- The unit will resume accurate altimeter readings when weather conditions settle.
- If experiencing rapidly changing weather, consider calibrating the sensor after conditions have settled.
- Extended periods of time in a fixed location
- For best accuracy, +/- 50 ft (~15 m), calibrate the pressure sensor to a known elevation on regular basis.
- Moving to and from climate controlled or pressurized environments (indoors to outdoors)
- Consider calibrating the sensor while you are outdoors.
- Debris blocking sensor port
- Fluctuating barometer data or lower/higher than expected altitude may be caused by water, or debris in the sensor port (located between the Start/Stop and Back/Lap buttons).
Select your product to confirm this information applies to you
Troubleshooting the Instinct Series Altimeter and Barometer
When experiencing incorrect readings from the altimeter or barometer sensors on a watch, there are a few factors to consider that might be impacting these readings, as well as some steps that can help increase their accuracy.
Understanding How These Sensors Work
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Troubleshooting the Barometer and Altimeter
Manually Selecting a Barometer Mode
It is possible to manually lock the watch into the Altimeter mode if your activity involves changes in elevation or lock it into the Barometer mode if your activity is in a relatively flat area. The Barometer mode is also useful if you are more interested in your watch notifying you of impending weather changes instead of elevation changes.
Calibrating the Altimeter
To maintain accurate readings when using the altimeter and barometer on these watches, the sensors need to be periodically calibrated. By default, the watch will calibrate automatically using the GPS elevation reading whenever a new activity is started. However, depending on the GPS signal strength, these elevations can be off by as much as +/- 400 feet.
The sensor can also be calibrated manually, providing an accuracy of within +/- 50 feet. To maintain this level of accuracy the watch will need to be periodically calibrated over time. For the best accuracy, it is recommended to do this hourly.
The watch offers two ways to calibrate; auto calibrate and manually calibrate.
Auto Calibration On
Setting auto calibration to On calibrates the sensor at the start of an activity. This will provide a consistent relative starting elevation if you do multiple activities at specific locations. When the timer is started the watch will try to determine the best elevation source to calibrate to, based on the following priority:
- Manual calibration immediately prior to starting the activity.
- Prior manual calibration point at the same location.
- Recent manual calibration, if the quality of the calibration is determined to be good enough.
- Map data (DEM - Digital Elevation Map), if available.
- Prior Connected DEM point at the same location:
- Connected DEM refers to elevation data from the Garmin Connect app on a paired smartphone.
- Connected DEM, if currently connected to a phone.
- Prior GPS point at the same location.
- Save Location immediately before starting the activity will also count toward calibration.
- GPS, if a good fix has been acquired:
- While acquiring a GPS fix, a ring, in the round dial window, will indicate progress in signal acquisition. If vertical speed settles to less than 0.1 m/s, the GPS elevation data will be considered good enough use for altimeter calibration. The dial will indicate this by displaying GPS with a checkmark.
Before starting the timer, the elevation data field on the watch will preview the calibrated elevation.
Throughout the activity, the watch uses GPS elevation, and DEM mapping data if available, to make adjustments to altitude for any altimeter drift due to pressure changes caused by a weather event during an activity.
Auto Calibration Nightly
The watch will calibrate the altimeter once every night during your sleep window set in Garmin Connect. If paired, the Garmin Connect app uses location data from the phone and compares it to the DEM information of the watch. This allows the nightly calibration feature to work better but is not required.
- When starting an activity, the watch will show current calibration and give the options to accept, or recalibrate.
- Nightly calibration is also performed when auto calibration is set to On.
To get location data from the phone to use for nightly calibration, location services will need to be enabled on your phone. For instructions on how to enable this on your phone:
It is important to follow every step listed to ensure the phone's location permission is properly enabled:
- Open the Garmin Connect app.
- Select
(upper left corner). - Select Settings.
- Select Phone Permissions.
- Select Manage Permissions. This will take you out of the Garmin Connect app and into the phone's app management settings.
- Select Permissions.
- Select Location.
- Select Allow all the time.
- If "Allow all the time" is not an available option, toggle Location on.
- Tap the back arrow at the top left to back out and save these settings.
- Power off and then power back on the Garmin device, and sync it through the Garmin Connect app.
Other Factors to Consider
Some factors that might impact the function of the altimeter and barometer include: rapidly moving air entering the sensor port while participating in high speed activities; climate controlled buildings which can have slightly different pressure indoors compared to the ambient pressure outside; and soap, dirt, or salts from sweat which can clog the sensor port.