The one barometer you would need on your watch! Of course, the phone app is powerful, too.
This app provides the following information using the built-in sensors:
- Atmospheric pressure
- Sea level pressure
- Latitude and longitude
- Boiling point of water based on current pressure
The application does not connect to the Internet. The barometer feature supports iPhone models newer than the iPhone6, iPad models newer than the iPad Air 2, and Apple Watch Series 3, 4 and 5.