Traditionally, barometers have been used to detect—and predict—short term changes in weather. Measured drops in pressure indicate rain is on the way. Sharply rising pressure signals clearer skies are ahead. But surely, Apple and Google didn’t conspire on this just to make more accurate weather predictions, right?

The barometer uses its atmospheric pressure readings to determine your altitude and more accurately determine how quickly you’re moving through an area.

Photo “Barometer” by Juan Pablo Olmo is licensed under CC BY 2.0