The most obvious reason for a barometer would be to provide accurate, on-location weather data. While that’s all good and well, the way developers manipulate and use this data in future apps could prove its true ability. We’re thinking something along the lines of apps that take external weather data and use it to manipulate various parameters in the same way a light sensor can help determine when to automatically adjust screen brightness. What sort of things would a barometer affect? We’ll wait for the developers to answer that one.