@yaron - welcome to the Rachio community. If there are personal weather stations in your area that do report actual precipitation, but are only on Weather Underground (www.wunderground.com) (which Rachio doesn’t use - yet) one can use the www.wufyi.com (use the beta version - Wufyi status update) service built and provided by community member @Gene to port Weather Underground station data over to PWSweather which Rachio reads from.
If there is a good site at your location one can also install and use their own weather station - again it will need to report to PWSweather directly or through wufyi for Rachio to be able to use the data.
If one is using “flex daily” schedules then one can go in manually on each zone and adjust the field water table to account for the rain.