Many weather enthusiasts are seeing sunny days -- the new iPhone 6 carries a barometer, which measures atmospheric pressure. The sensor is mostly intended to provide elevation data to fitness and other apps (GPS satellites do a poor job of triangulating elevation, with an error rate of upwards of 60 feet +\-).
While barometric pressure readings can be subject to the vagaries of local conditions, accuracy may be an issue for weather-gathering apps. Combined with geo-located map data, however, you will have accurate on-point readings. Only flight requires accurate elevation readings that GPS can't give -- why you calibrate your baramoter at the apron of the departure runway, which has MSL marked on the chart. Using statistical sampling could overcome some data accumulation problems, as well.
Anytime scientists can gather more data, we all benefit. Look at Google's traffic display on their maps -- crowdsourcing works.