Need to know of an app that will tell me the barometric pressure in my area and if it is rising or falling.

Hi everyone, I am needing to know of an iOS app that will tell me the barometric pressure in my area, and if it is rising or falling. Siri used to do this, but it is become very unreliable since updating. Does anyone have any ideas? My phone is running iOS 7 because it is a for S my iPod is running the latest iOS 8. Thanks in advance.
All the best,
Cat