The title says it all

This is a hyper-focal weather reporting app that tells you (with impressive accuracy) what the weather is now, and what it will most likely be in the near future. What really impressed me though, was the addition of a reporting system. If for any reason the weather on your screen doesnt match the weather overhead, you can give dark sky a real time weather update, and they use that data to fine tune their predictive analytics.

D Espo about Dark Sky Weather