This app was mentioned in 3 comments, with an average of 1.33 upvotes
S4's have a lot of sensors that most phones don't have anymore. I use this app running in my bedroom all of the time to show temp, humidity, barometric pressure and light - https://play.google.com/store/apps/details?id=pl.komur.android.galaxys4sensors
This? because it doesn't work since there's no temp and humidity sensors to communicate with.
Native support would be awesome. Until then:
https://play.google.com/store/apps/details?id=pl.komur.android.galaxys4sensors