Hold MENU, and select Settings > Sensors & Accessories > Barometer.

Calibrate

Manually calibrates the barometer sensor.

Plot

Sets the time scale for the chart in the barometer glance.

Storm Alert

Sets the rate of barometric pressure change that triggers a storm alert.

Sensor Mode

Sets the mode for the sensor. The Auto option uses both the altimeter and barometer according to your movement. You can use the Altimeter Only option when your activity involves changes in altitude, or the Barometer Only option when your activity does not involve changes in altitude.

Pressure

Sets how the watch displays pressure data.