As rainfall amount varies significantly even in a small area, the weather data could be not accurate enough for your place. Netro still watered your zone after heavy rain, this might because the weather forecast said there was going to be a small rain but it turns out to be a big one. The soil moisture level will not increase a lot after small rain so Netro still watered your zones to keep the soil mosute level up. You can go to the Home page, tap the moisture level(%) in a circle in the zone area to check the soil moisture level of your zone by week/month.
Of course, all weather forecast could be wrong. Netro tries the best to provide accurate watering schedule even with incorrect forecast. First, we periodically update the weather data, once the weather data is changed, we update the un-executed schedules ASAP. Second, we re-check the weather data for the past, update our model, and adjust following schedules accordingly. For example, Netro may not water today due to large rainfall from forecast data. The next day, Netro re-check the weather data, if no rainfall found and your soil is dry enough, Netro will water accordingly.
I have forwarded your suggestion about adding a feature to update actual rainfall to our develop team and we will support this feature in the future version of the app.
We understand you are frustrated and we are very sorry. Darksky cannot be changed and currently we are developing weather underground pws.
As a workaround, you can customize the weather restrictions. This is in setting -> preferences -> rain. By default, Netro skip schedules today and tomorrow if today rains more than 0.2 inch. You can customize it, like I want to skip the schedules on the day after tomorrow as well, or I want to skip if rain more than 0.5 inch.
You can also add a rain delay, please go to the Schedule page, press the + sign on the right upper corner and select Rain Delay. If you want to review the created rain delays, you can go Settings->Restrictions and your the rain delays will be shown. You can edit and delete the existing rain delays too.
Please let us know if my answer helps.