The new iPhones have a barometric pressure sensor built in so this app works completely without internet. The handy marker helps you keep track of changes in the barometric pressure and let's you predict weather changes! ... The Altimeter helps you track your altitude changes based on the change of pressure.

How accurate is iPhone barometer?

According to online reports, the iPhone6 has a Bosch BMP280 sensor (see image), with fairly good numbers: absolute accuracy of +-1 hPa and relative accuracy for pressure changes of +-. ... 1 hPa (normal sea level pressure is roughly 1013 hPa).

Do cell phones have barometers?

Barometers measure air pressure. ... If you use a smartphone, it probably already has a built-in barometer. Phone manufacturers include barometers to improve GPS elevation results, because they can be adversely affected by atmospheric pressure.