Currently Rachio just blindly uses the reported weather station data. However, especially with PWS data, somtimes the data is inaccurate.
Several times the nearest wether station has reported 6" rain in the middle of summer, and Rachio has decided to kill all my plants by not watering for a week.
It's pretty trivial in this case to see that all the other nearby wether statios reported zero rain, and 6" is far outside the band of historic rainfall in California summers. So it should be possible to automatically ignore the fautly data point or automatically blacklist the weather station.