Erroneous ET0 in Rachio compared to 'official' data

Typically my rachio gen 3 controller has ET0 readings almost the same (Weather Intelligence plus) as what is reported by the California CIMIS Station #153 which is 10 miles away and in the same microclimate. I know this because I have an unconnected dummy Rachio zone with crop factor set to 1.0 and I tend to check it on and off comparing it to the official one. Last week, we had a weather event with heavy dry winds (‘Santa Anas’) and the rachio ET0 was about 0.51inches while the CIMIS one reported 0.21inches. for the day. Any explanation for this discrepancy? Other than a couple of days like this, my ET0 matches almost exactly with the CIMIS one. I can understand that there could have been locally high gusts of winds compared to the CIMIS one. But I’ve never seen this high a ET0 number.


I am having the same issue in Ventura County. I work for a sod farm and i’ve noticed that when there is a wind event, the ETO’s are way off. Does anyone know if Rachio is looking into this issue?

Agreed…
One question why do you have AD at 100 percent?

On 10/25 it does show half inch less moisture and accounts for the CIMIS reporting ETO …it looks close.

Are you on WI only and not a WS in the area? I wonder if the UV reporting and wind delay had something to do with it, as occured in our areas gusts upwards 60 plus and hot and dry Santa Anas.

My sites , were dry as the Mojave and with the wind delay my fall color plantings are stressed.

I wonder if the CIMIS was correct as it was the same as well and then again matched Rachio on 10/26