The idea of putting temperature and humidity sensor is kinda mindboggling.
The benefit of having it in a mobile device, with the combination of gps data, temperature and humidity in any location can be precisely measured and logged. Yet, when it is in a smartphone, the challenge is no one knows where the phone is currently kept. There will certainly be temperature difference when it is kept in the front pocket of man's shirt vs when it is kept in a woman's purse.
In working on this slideshow, I was amazed how the Samsung Galaxy S4 smartphone, for this one brief moment, is really influential and a good example of these trends: it has humidity and temperature sensors, IR sensors for gesture recognition, ambient light sensors, the usual sensors that make the camera work, pressure (barometer), accelerometers -- all i need is my fuel cell sensor so the phone can be its own breathalyzer. If you get a chance, take a look at iFixit's teardown photos here. It's a pretty amazing piece of engineering.